US20100253152A1 - Long range low frequency resonator - Google Patents

Long range low frequency resonator Download PDF

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US20100253152A1
US20100253152A1 US12717559 US71755910A US2010253152A1 US 20100253152 A1 US20100253152 A1 US 20100253152A1 US 12717559 US12717559 US 12717559 US 71755910 A US71755910 A US 71755910A US 2010253152 A1 US2010253152 A1 US 2010253152A1
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resonator
system
high
frequency
γ
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Aristeidis Karalis
Andre B. Kurs
Robert Moffatt
John D. Joannopoulos
Peter H. Fisher
Marin Soljacic
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Massachusetts Institute of Technology
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Massachusetts Institute of Technology
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/10Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling
    • H02J50/12Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling of the resonant type
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B60VEHICLES IN GENERAL
    • B60LELECTRIC EQUIPMENT OR PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES, IN GENERAL
    • B60L11/00Electric propulsion with power supplied within the vehicle
    • B60L11/18Electric propulsion with power supplied within the vehicle using power supply from primary cells, secondary cells, or fuel cells
    • B60L11/1809Charging electric vehicles
    • B60L11/182Charging electric vehicles by inductive energy transfer
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01QANTENNAS, i.e. RADIO AERIALS
    • H01Q7/00Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01QANTENNAS, i.e. RADIO AERIALS
    • H01Q9/00Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
    • H01Q9/04Resonant antennas
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J17/00Systems for supplying or distributing electric power by electromagnetic waves
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J5/00Circuit arrangements for transfer of electric power between ac networks and dc networks
    • H02J5/005Circuit arrangements for transfer of electric power between ac networks and dc networks with inductive power transfer
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/80Circuit arrangements or systems for wireless supply or distribution of electric power involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/90Circuit arrangements or systems for wireless supply or distribution of electric power involving detection or optimisation of position, e.g. alignment
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/02Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from ac mains by converters
    • H02J7/022Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from ac mains by converters characterised by the type of converter
    • H02J7/025Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from ac mains by converters characterised by the type of converter using non-contact coupling, e.g. inductive, capacitive
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B5/00Near-field transmission systems, e.g. inductive loop type
    • H04B5/0025Near field system adaptations
    • H04B5/0037Near field system adaptations for power transfer
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B60VEHICLES IN GENERAL
    • B60LELECTRIC EQUIPMENT OR PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES, IN GENERAL
    • B60L2210/00Converter types
    • B60L2210/20AC to AC converters
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02TCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00Road transport of goods or passengers
    • Y02T10/60Other road transportation technologies with climate change mitigation effect
    • Y02T10/70Energy storage for electromobility
    • Y02T10/7005Batteries
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02TCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00Road transport of goods or passengers
    • Y02T10/60Other road transportation technologies with climate change mitigation effect
    • Y02T10/70Energy storage for electromobility
    • Y02T10/7072Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02TCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00Road transport of goods or passengers
    • Y02T10/60Other road transportation technologies with climate change mitigation effect
    • Y02T10/72Electric energy management in electromobility
    • Y02T10/7208Electric power conversion within the vehicle
    • Y02T10/725AC to AC power conversion
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02TCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T90/00Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02T90/10Technologies related to electric vehicle charging
    • Y02T90/12Electric charging stations
    • Y02T90/122Electric charging stations by inductive energy transmission
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02TCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T90/00Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02T90/10Technologies related to electric vehicle charging
    • Y02T90/12Electric charging stations
    • Y02T90/127Converters or inverters for charging
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02TCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T90/00Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02T90/10Technologies related to electric vehicle charging
    • Y02T90/14Plug-in electric vehicles
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00Metal working
    • Y10T29/49Method of mechanical manufacture
    • Y10T29/49002Electrical device making
    • Y10T29/4902Electromagnet, transformer or inductor

Abstract

Described herein are embodiments of a wireless power transmitter system for transmitting power to at least one high-Q resonator that includes a connection to a source of line power, a modulating part, which converts said line power to create a first frequency of lower than 1 MHz, and a transmitter part, including a transmitting high-Q resonator formed of a conductive loop with a capacitor that brings said high-Q resonator to resonance at said first frequency, and which produces a magnetic field based on said source of line power, said transmitter part having a Q factor at said frequency, where said Q factor is at least 300.

Description

    CROSS-REFERENCE TO RELATED APPLICATIONS
  • This application is a continuation of U.S. patent application Ser. 12/688,339 ('339 application) filed Jan. 15, 2010, the entirety of which is incorporated herein by reference. The '339 application is a continuation to U.S. patent application Ser. 12/055,963 ('963 Application), filed Mar. 26, 2008 the entirety of which is incorporated herein by reference. The ‘963 application claims the benefit of the following provisional applications, each of which is incorporated herein by reference in its entirety: U.S. Provisional Patent Application 60/908,383 filed Mar. 27, 2007; and U.S. Provisional Patent Application 60/908,666, filed Mar. 28, 2007.
  • The '963 application is a continuation-in-part of co-pending United States Patent Application entitled WIRELESS NON-RADIATIVE ENERGY TRANSFER filed on Jul. 5, 2006 and having Ser. No. 11/481,077.('077 Application), the entirety of which is incorporated herein by reference. The '077 Application claims the benefit of provisional application Ser. No. 60/698,442 filed Jul. 12, 2005 ('442 Application), the entirety of which is incorporated herein by reference.
  • The '963 application, pursuant to U.S.C. §120 and U.S.C. §363, is a continuation-in-part of International Application No. PCT/US2007/070892, filed Jun. 11, 2007, which is incorporated herein by reference in its entirety, and which claims priority to the following provisional applications, each of which is incorporated herein by reference in its entirety: U.S. Provisional Patent Application 60/908,383 filed Mar. 27, 2007; and U.S. Provisional Patent Application 60/908,666, filed Mar. 28, 2007.
  • STATEMENT REGARDING GOVERNMENT FUNDING
  • This invention was made with government support awarded by the National Science Foundation under Grant No. DMR 02-13282. The government has certain rights in this invention.
  • BACKGROUND
  • The disclosure relates to wireless energy transfer. Wireless energy transfer may for example, be useful in such applications as providing power to autonomous electrical or electronic devices.
  • Radiative modes of omni-directional antennas (which work very well for information transfer) are not suitable for such energy transfer, because a vast majority of energy is wasted into free space. Directed radiation modes, using lasers or highly-directional antennas, can be efficiently used for energy transfer, even for long distances (transfer distance LTRANS
    Figure US20100253152A1-20101007-P00001
    LDEV, where LDEV is the characteristic size of the device and/or the source), but require existence of an uninterruptible line-of-sight and a complicated tracking system in the case of mobile objects. Some transfer schemes rely on induction, but are typically restricted to very close-range (LTRANS
    Figure US20100253152A1-20101007-P00002
    LDEV or low power (˜mW) energy transfers.
  • The rapid development of autonomous electronics of recent years (e.g. laptops, cell-phones, house-hold robots, that all typically rely on chemical energy storage) has led to an increased need for wireless energy transfer.
  • SUMMARY
  • The inventors have realized that resonant objects with coupled resonant modes having localized evanescent field patterns may be used for non-radiative wireless energy transfer. Resonant objects tend to couple, while interacting weakly with other off-resonant environmental objects. Typically, using the techniques described below, as the coupling increases, so does the transfer efficiency. In some embodiments, using the below techniques, the energy-transfer rate can be larger than the energy-loss rate. Accordingly, efficient wireless energy-exchange can be achieved between the resonant objects, while suffering only modest transfer and dissipation of energy into other off-resonant objects. The nearly-omnidirectional but stationary (non-lossy) nature of the near field makes this mechanism suitable for mobile wireless receivers. Various embodiments therefore have a variety of possible applications including for example, placing a source (e.g. one connected to the wired electricity network) on the ceiling of a factory room, while devices (robots, vehicles, computers, or similar) are roaming freely within the room. Other applications include power supplies for electric-engine buses and/or hybrid cars and medical implantable devices.
  • In some embodiments, resonant modes are so-called magnetic resonances, for which most of the energy surrounding the resonant objects is stored in the magnetic field; i.e. there is very little electric field outside of the resonant objects. Since most everyday materials (including animals, plants and humans) are non-magnetic, their interaction with magnetic fields is minimal. This is important both for safety and also to reduce interaction with the extraneous environmental objects.
  • In one aspect, an apparatus is disclosed for use in wireless energy transfer, which includes a first resonator structure configured to transfer energy with a second resonator structure over a distance D greater than a characteristic size L2 of the second resonator structure. In some embodiments, D is also greater than one or more of: a characteristic size L1 of the first resonator structure, a characteristic thickness T1 of the first resonator structure, and a characteristic width W1 of the first resonator structure. The energy transfer is mediated by evanescent-tail coupling of a resonant field of the first resonator structure and a resonant field of the second resonator structure. The apparatus may include any of the following features alone or in combination.
  • In some embodiments, the first resonator structure is configured to transfer energy to the second resonator structure. In some embodiments, the first resonator structure is configured to receive energy from the second resonator structure. In some embodiments, the apparatus includes the second resonator structure.
  • In some embodiments, the first resonator structure has a resonant angular frequency ω1, a Q-factor Q1, and a resonance width Γ1, the second resonator structure has a resonant angular frequency ω2, a Q-factor Q2, and a resonance width Γ2, and the energy transfer has a rate κ. In some embodiments, the absolute value of the difference of the angular frequencies ω1 and ω2 is smaller than the broader of the resonant widths Γ1 and Γ2.
  • In some embodiments Q1>100 and Q2>100, Q1>300 and Q2>300, Q1>500 and Q2>500, or Q1>1000 and Q2>1000. In some embodiments, Q1>100 or Q2>100, Q1>300 or Q2>300, Q1>500 or Q2>500, or Q1>1000 or Q2>1000.
  • In some embodiments, the coupling to loss ratio
  • κ Γ 1 Γ 2 > 0.5 , κ Γ 1 Γ 2 > 1 , κ Γ 1 Γ 2 > 2 , or κ Γ 1 Γ 2 > 5.
  • In some such embodiments, D/L2 may be as large as 2, as large as 3, as large as 5, as large as 7, or as large as 10.
  • In some embodiments, Q1>1000 and Q2>1000, and the coupling to loss ratio
  • κ Γ 1 Γ 2 > 10 , κ Γ 1 Γ 2 > 25 , or κ Γ 1 Γ 2 > 40.
  • In some such embodiments, D/L2 may be as large as 2, as large as 3, as large as 5, as large as 7, as large as 10.
  • In some embodiments, Qκ=ω/2κ is less than about 50, less than about 200, less than about 500, or less than about 1000. In some such embodiments, D/L2 is as large as 2, as large as 3, as large as 5, as large as 7, or as large as 10.
  • In some embodiments, the quantity κ/√{square root over (Γ1Γ2)} is maximized at an angular frequency {tilde over (ω)} with a frequency width {tilde over (Γ)} around the maximum, and the absolute value of the difference of the angular frequencies ω1 and {tilde over (ω)} is smaller than the width {tilde over (Γ)}, and the absolute value of the difference of the angular frequencies ω2 and {tilde over (ω)} is smaller than the width {tilde over (Γ)}.
  • In some embodiments, the energy transfer operates with an efficiency ηwork greater than about 1%, greater than about 10%, greater than about 30%, greater than about 50%, or greater than about 80%.
  • In some embodiments, the energy transfer operates with a radiation loss ηrad less that about 10%. In some such embodiments the coupling to loss ratio
  • κ Γ 1 Γ 2 0.1 .
  • In some embodiments, the energy transfer operates with a radiation loss ηrad less that about 1%. In some such embodiments, the coupling to loss ratio
  • κ Γ 1 Γ 2 1.
  • In some embodiments, in the presence of a human at distance of more than 3 cm from the surface of either resonant object, the energy transfer operates with a loss to the human ηh of less than about 1%. In some such embodiments the coupling to loss ratio
  • κ Γ 1 Γ 2 1.
  • In some embodiments, in the presence of a human at distance of more than 10 cm from the surface of either resonant object, the energy transfer operates with a loss to the human ηh of less than about 0.2%. In some such embodiments the coupling to loss ratio
  • κ Γ 1 Γ 2 1.
  • In some embodiments, during operation, a device coupled to the first or second resonator structure with a coupling rate Γwork receives a usable power Pwork from the resonator structure.
  • In some embodiments, Pwork is greater than about 0.01 Watt, greater than about 0.1 Watt, greater than about 1 Watt, or greater than about 10 Watt.
  • In some embodiments, if the device is coupled to the first resonator, then

  • ½[(Γwork1)2−1]/(κ/√{square root over (Γ1Γ2)})2≦2, or

  • ¼[(Γwork1)2−1]/(κ/√{square root over (Γ1Γ2)})2≦4, or
  • ⅛[(Γwork1)2−1]/(κ/√{square root over (Γ1Γ2)})2≦8, and, if the device is coupled to the second resonator, then ½[(Γwork2)2−1]/(κ/√{square root over (Γ1Γ2)})2≦2, or

  • ¼[(Γwork2)2−1]/(κ/√{square root over (Γ1Γ2)})2≦4, or

  • ⅛[(Γwork2)2−1]/(κ/√{square root over (Γ1Γ2)})2≦8, or
  • In some embodiments, the device includes an electrical or electronic device. In some embodiments, the device includes a robot (e.g. a conventional robot or a nano-robot). In some embodiments, the device includes a mobile electronic device (e.g. a telephone, or a cell-phone, or a computer, or a laptop computer, or a personal digital assistant (PDA)). In some embodiments, the device includes an electronic device that receives information wirelessly (e.g. a wireless keyboard, or a wireless mouse, or a wireless computer screen, or a wireless television screen). In some embodiments, the device includes a medical device configured to be implanted in a patient (e.g. an artificial organ, or implant configured to deliver medicine). In some embodiments, the device includes a sensor. In some embodiments, the device includes a vehicle (e.g. a transportation vehicle, or an autonomous vehicle).
  • In some embodiments, the apparatus further includes the device.
  • In some embodiments, during operation, a power supply coupled to the first or second resonator structure with a coupling rate Γsupply drives the resonator structure at a frequency f and supplies power Ptotal. In some embodiments, the absolute value of the difference of the angular frequencies ω=2πf and ω1 is smaller than the resonant width Γ1, and the absolute value of the difference of the angular frequencies ω=2πf and ω2 is smaller than the resonant width Γ2. In some embodiments, f is about the optimum efficiency frequency.
  • In some embodiments, if the power supply is coupled to the first resonator,

  • then ½≦[(Γsupply1)2−1]/(κ/√{square root over (Γ1Γ2)})2≦2, or

  • ¼≦[(Γsupply1)2−1]/(κ/√{square root over (Γ1Γ2)})2≦4, or

  • ⅛≦[(Γsupply1)2−1]/(κ/√{square root over (Γ1Γ2)})2≦8, or
  • second resonator, then ½≦[(Γsupply2)2−1]/(κ/√{square root over (Γ1Γ2)})2≦2, or

  • ¼≦[(Γsupply2)2−1]/(κ/√{square root over (Γ1Γ2)})2≦4, or

  • ⅛≦[(Γsupply2)2−1]/(κ/√{square root over (Γ1Γ2)})2≦8, or
  • In some embodiments, the apparatus further includes the power source. In some embodiments, the resonant fields are electromagnetic. In some embodiments, f is about 50 GHz or less, about 1 GHz or less, about 100 MHz or less, about 10 MHz or less, about 1 MHz or less, about 100 KHz or less, or about 10 kHz or less. In some embodiments, f is about 50 GHz or greater, about 1 GHz or greater, about 100 MHz or greater, about 10 MHz or greater, about 1 MHz or greater, about 100 kHz or greater, or about 10 kHz or greater. In some embodiments, f is within one of the frequency bands specially assigned for industrial, scientific and medical (ISM) equipment.
  • In some embodiments, the resonant fields are primarily magnetic in the area outside of the resonant objects. In some such embodiments, the ratio of the average electric field energy to average magnetic filed energy at a distance Dp from the closest resonant object is less than 0.01, or less than 0.1. In some embodiments, LR is the characteristic size of the closest resonant object and Dp/LR is less than 1.5, 3, 5, 7, or 10.
  • In some embodiments, the resonant fields are acoustic. In some embodiments, one or more of the resonant fields include a whispering gallery mode of one of the resonant structures.
  • In some embodiments, one of the first and second resonator structures includes a self resonant coil of conducting wire, conducting Litz wire, or conducting ribbon. In some embodiments, both of the first and second resonator structures include self resonant coils of conducting wire, conducting Litz wire, or conducting ribbon. In some embodiments, both of the first and second resonator structures include self resonant coils of conducting wire or conducting Litz wire or conducting ribbon, and Q1>300 and Q2>300.
  • In some embodiments, one or more of the self resonant conductive wire coils include a wire of length l and cross section radius a wound into a helical coil of radius r, height h and number of turns N. In some embodiments, N=√{square root over (l2−h2)}/2πr.
  • In some embodiments, for each resonant structure r is about 30 cm, h is about 20 cm, a is about 3 mm and N is about 5.25, and, during operation, a power source coupled to the first or second resonator structure drives the resonator structure at a frequency f. In some embodiments, f is about 10.6 MHz. In some such embodiments, the coupling to loss ratio
  • κ Γ 1 Γ 2 40 , κ Γ 1 Γ 2 15 , or κ Γ 1 Γ 2 5 , or κ Γ 1 Γ 2 1.
  • In some
    such embodiments D/LR is as large as about 2, 3, 5, or 8.
  • In some embodiments, for each resonant structure r is about 30 cm, h is about 20 cm, a is about 1 cm and N is about 4, and, during operation, a power source coupled to the first or second resonator structure drives the resonator structure at a frequency f. In some embodiments, f is about 13.4 MHz. In some such embodiments, the coupling to loss ratio
  • κ Γ 1 Γ 2 70 , κ Γ 1 Γ 2 19 , or κ Γ 1 Γ 2 8 , or κ Γ 1 Γ 2 3.
  • In some such embodiments D/LR is as large as about 3, 5, 7, or 10.
  • In some embodiments, for each resonant structure r is about 10 cm, h is about 3 cm, a is about 2 mm and N is about 6, and, during operation, a power source coupled to the first or second resonator structure drives the resonator structure at a frequency f. In some embodiments, f is about 21.4 MHz. In some such embodiments, the coupling to loss ratio
  • κ Γ 1 Γ 2 59 , κ Γ 1 Γ 2 15 , or κ Γ 1 Γ 2 6 , or κ Γ 1 Γ 2 2.
  • In some such embodiments D/LR is as large as about 3, 5, 7, or 10.
  • In some embodiments, one of the first and second resonator structures includes a capacitively loaded loop or coil of conducting wire, conducting Litz wire, or conducting ribbon. In some embodiments, both of the first and second resonator structures include capacitively loaded loops or coils of conducting wire, conducting Litz wire, or conducting ribbon. In some embodiments, both of the first and second resonator structures include capacitively loaded loops or coils of conducting wire or conducting Litz wire or conducting ribbon, and Q1>300 and Q2>300.
  • In some embodiments, the characteristic size LR of the resonator structure receiving energy from the other resonator structure is less than about 1 cm and the width of the conducting wire or Litz wire or ribbon of said object is less than about 1 mm, and, during operation, a power source coupled to the first or second resonator structure drives the resonator structure at a frequency f. In some embodiments, f is about 380 MHz. In some such embodiments, the coupling to loss ratio
  • κ Γ 1 Γ 2 14.9 , κ Γ 1 Γ 2 3.2 , κ Γ 1 Γ 2 1.2 , or κ Γ 1 Γ 2 0.4 .
  • In some such embodiments, D/LR is as large as about 3, about 5, about 7, or about 10.
  • In some embodiments, the characteristic size of the resonator structure receiving energy from the other resonator structure LR is less than about 10 cm and the width of the conducting wire or Litz wire or ribbon of said object is less than about 1 cm, and, during operation, a power source coupled to the first or second resonator structure drives the resonator structure at a frequency f. In some embodiments, f is about 43 MHz. In some such embodiments, the coupling to loss ratio
  • κ Γ 1 Γ 2 15.9 , κ Γ 1 Γ 2 4.3 , κ Γ 1 Γ 2 1.8 , or κ Γ 1 Γ 2 0.7 .
  • In some such embodiments, D/LR is as large as about 3, about 5, about 7, or about 10.
  • In some embodiments, the characteristic size LR of the resonator structure receiving energy from the other resonator structure is less than about 30 cm and the width of the conducting wire or Litz wire or ribbon of said object is less than about 5 cm, and, during operation, a power source coupled to the first or second resonator structure drives the resonator structure at a frequency f. In some such embodiments, f is about 9 MHz. In some such embodiments, the coupling to loss ratio
  • κ Γ 1 Γ 2 67.4 , κ Γ 1 Γ 2 17.8 , κ Γ 1 Γ 2 7.1 , or κ Γ 1 Γ 2 2.7 .
  • In some such embodiments, D/LR is as large as about 3, about 5, about 7, or about 10.
  • In some embodiments, the characteristic size of the resonator structure receiving energy from the other resonator structure LR is less than about 30 cm and the width of the conducting wire or Litz wire or ribbon of said object is less than about 5 mm, and, during operation, a power source coupled to the first or second resonator structure drives the resonator structure at a frequency f. In some embodiments, f is about 17 MHz. In some such embodiments, the coupling to loss ratio
  • κ Γ 1 Γ 2 6.3 , κ Γ 1 Γ 2 1.3 , κ Γ 1 Γ 2 0.5 . , or κ Γ 1 Γ 2 0.2 .
  • In some such embodiments, D/LR is as large as about 3, about 5, about 7, or about 10.
  • In some embodiments, the characteristic size LR of the resonator structure receiving energy from the other resonator structure is less than about 1 m, and the width of the conducting wire or Litz wire or ribbon of said object is less than about 1 cm, and, during operation, a power source coupled to the first or second resonator structure drives the resonator structure at a frequency f. In some embodiments, f is about 5MHz. In some such embodiments, the coupling to loss ratio
  • κ Γ 1 Γ 2 6.8 , κ Γ 1 Γ 2 1.4 , κ Γ 1 Γ 2 0.5 , κ Γ 1 Γ 2 0.2 .
  • In some such embodiments, D/LR is as large as about 3, about 5, about 7, or about 10.
  • In some embodiments, during operation, one of the resonator structures receives a usable power Pw from the other resonator structure, an electrical current Is flows in the resonator structure which is transferring energy to the other resonant structure, and the ratio
  • I s P w
  • is less than about 5 Amps/√{square root over (Watts)} or less than about 2 Amps/√{square root over (Watts)}. In some embodiments, during operation, one of the resonator structures receives a usable power Pw from the other resonator structure, a voltage difference Vs appears across the capacitive element of the first resonator structure, and the ratio
  • V s P w
  • is less than about 2000 Volts/√{square root over (Watts)} or less than about 4000 Volts/√{square root over (Watts)}.
  • In some embodiments, one of the first and second resonator structures includes a inductively loaded rod of conducting wire or conducting Litz wire or conducting ribbon. In some embodiments, both of the first and second resonator structures include inductively loaded rods of conducting wire or conducting Litz wire or conducting ribbon. In some embodiments, both of the first and second resonator structures include inductively loaded rods of conducting wire or conducting Litz wire or conducting ribbon, and Q1>300 and Q2>300.
  • In some embodiments, the characteristic size of the resonator structure receiving energy from the other resonator structure LR is less than about 10 cm and the width of the conducting wire or Litz wire or ribbon of said object is less than about 1 cm, and, during operation, a power source coupled to the first or second resonator structure drives the resonator structure at a frequency f. In some embodiments, f is about 14 MHz. In some such embodiments, the coupling to loss ratio
  • κ Γ 1 Γ 2 32 , κ Γ 1 Γ 2 5.8 , κ Γ 1 Γ 2 2 , or κ Γ 1 Γ 2 0.6 .
  • In some such embodiments, D/LR is as large as about 3, about 5, about 7, or about 10.
  • In some embodiments, the characteristic size LR of the resonator structure receiving energy from the other resonator structure is less than about 30 cm and the width of the conducting wire or Litz wire or ribbon of said object is less than about 5 cm, and, during operation, a power source coupled to the first or second resonator structure drives the resonator structure at a frequency f. In some such embodiments, f is about 2.5 MHz. In some such embodiments, the coupling to loss ratio
  • κ Γ 1 Γ 2 105 , κ Γ 1 Γ 2 19 , κ Γ 1 Γ 2 6.6 , or κ Γ 1 Γ 2 2.2 .
  • In some such embodiments, D/LR is as large as about 3, about 5, about 7, or about 10.
  • In some embodiments, one of the first and second resonator structures includes a dielectric disk. In some embodiments, both of the first and second resonator structures include dielectric disks. In some embodiments, both of the first and second resonator structures include dielectric disks, and Q1>300 and Q2>300.
  • In some embodiments, the characteristic size of the resonator structure receiving energy from the other resonator structure is LR and the real part of the permittivity of said resonator structure ε is less than about 150. In some such embodiments, the coupling to loss ratio
  • κ Γ 1 Γ 2 42.4 , κ Γ 1 Γ 2 6.5 , κ Γ 1 Γ 2 2.3 , κ Γ 1 Γ 2 0.5 .
  • In some such embodiments, D/LR is as large as about 3, about 5, about 7, or about 10.
  • In some embodiments, the characteristic size of the resonator structure receiving energy from the other resonator structure is LR and the real part of the permittivity of said resonator structure ε is less than about 65. In some such embodiments, the coupling to loss ratio
  • κ Γ 1 Γ 2 30.9 , κ Γ 1 Γ 2 2.3 , or κ Γ 1 Γ 2 0.5 .
  • In some such embodiments, D/LR is as large as about 3, about 5, about 7.
  • In some embodiments, at least one of the first and second resonator structures includes one of: a dielectric material, a metallic material, a metallodielectric object, a plasmonic material, a plasmonodielectric object, a superconducting material.
  • In some embodiments, at least one of the resonators has a quality factor greater than about 5000, or greater than about 10000.
  • In some embodiments, the apparatus also includes a third resonator structure configured to transfer energy with one or more of the first and second resonator structures, where the energy transfer between the third resonator structure and the one or more of the first and second resonator structures is mediated by evanescent-tail coupling of the resonant field of the one or more of the first and second resonator structures and a resonant field of the third resonator structure.
  • In some embodiments, the third resonator structure is configured to transfer energy to one or more of the first and second resonator structures.
  • In some embodiments, the first resonator structure is configured to receive energy from one or more of the first and second resonator structures.
  • In some embodiments, the first resonator structure is configured to receive energy from one of the first and second resonator structures and transfer energy to the other one of the first and second resonator structures.
  • Some embodiments include a mechanism for, during operation, maintaining the resonant frequency of one or more of the resonant objects. In some embodiments, the feedback mechanism comprises an oscillator with a fixed frequency and is configured to adjust the resonant frequency of the one or more resonant objects to be about equal to the fixed frequency. In some embodiments, the feedback mechanism is configured to monitor an efficiency of the energy transfer, and adjust the resonant frequency of the one or more resonant objects to maximize the efficiency.
  • In another aspect, a method of wireless energy transfer is disclosed, which method includes providing a first resonator structure and transferring energy with a second resonator structure over a distance D greater than a characteristic size L2 of the second resonator structure. In some embodiments, D is also greater than one or more of: a characteristic size L1 of the first resonator structure, a characteristic thickness T1 of the first resonator structure, and a characteristic width W1 of the first resonator structure. The energy transfer is mediated by evanescent-tail coupling of a resonant field of the first resonator structure and a resonant field of the second resonator structure.
  • In some embodiments, the first resonator structure is configured to transfer energy to the second resonator structure. In some embodiments, the first resonator structure is configured to receive energy from the second resonator structure.
  • In some embodiments, the first resonator structure has a resonant angular frequency ω1, a Q-factor Q1, and a resonance width Γ1 , the second resonator structure has a resonant angular frequency ω2, a Q-factor Q2, and a resonance width Γ2, and the energy transfer has a rate κ. In some embodiments, the absolute value of the difference of the angular frequencies ω1 and ω2 is smaller than the broader of the resonant widths Γ1 and Γ2.
  • In some embodiments, the coupling to loss ratio
  • κ Γ 1 Γ 2 > 0.5 , κ Γ 1 Γ 2 > 1 , κ Γ 1 Γ 2 > 2 , or κ Γ 1 Γ 2 > 5.
  • In some such embodiments, D/L2 may be as large as 2, as large as 3, as large as 5, as large as 7, or as large as 10.
  • In another aspect, an apparatus is disclosed for use in wireless information transfer which includes a first resonator structure configured to transfer information by transferring energy with a second resonator structure over a distance D greater than a characteristic size L2 of the second resonator structure. In some embodiments, D is also greater than one or more of: a characteristic size L1 of the first resonator structure, a characteristic thickness T1 of the first resonator structure, and a characteristic width W1 of the first resonator structure. The energy transfer is mediated by evanescent-tail coupling of a resonant field of the first resonator structure and a resonant field of the second resonator structure.
  • In some embodiments, the first resonator structure is configured to transfer energy to the second resonator structure. In some embodiments, the first resonator structure is configured to receive energy from the second resonator structure. In some embodiments the apparatus includes, the second resonator structure.
  • In some embodiments, the first resonator structure has a resonant angular frequency ω1, a Q-factor Q1, and a resonance width Γ1, the second resonator structure has a resonant angular frequency ω2, a Q-factor Q2, and a resonance width Γ2, and the energy transfer has a rate κ. In some embodiments, the absolute value of the difference of the angular frequencies ω1 and ω2 is smaller than the broader of the resonant widths Γ1 and Γ2.
  • In some embodiments, the coupling to loss ratio
  • κ Γ 1 Γ 2 > 0.5 , κ Γ 1 Γ 2 > 1 , κ Γ 1 Γ 2 > 2 , or κ Γ 1 Γ 2 > 5.
  • In some such embodiments, D/L2 may be as large as 2, as large as 3, as large as 5, as large as 7, or as large as 10.
  • In another aspect, a method of wireless information transfer is disclosed, which method includes providing a first resonator structure and transferring information by transferring energy with a second resonator structure over a distance D greater than a characteristic size L2 of the second resonator structure. In some embodiments, D is also greater than one or more of: a characteristic size L1 of the first resonator structure, a characteristic thickness T1 of the first resonator structure, and a characteristic width W1 of the first resonator structure. The energy transfer is mediated by evanescent-tail coupling of a resonant field of the first resonator structure and a resonant field of the second resonator structure.
  • In some embodiments, the first resonator structure is configured to transfer energy to the second resonator structure. In some embodiments, the first resonator structure is configured to receive energy from the second resonator structure.
  • In some embodiments, the first resonator structure has a resonant angular frequency ω1, a Q-factor Q1, and a resonance width Γ1, the second resonator structure has a resonant angular frequency ω2, a Q-factor Q2, and a resonance width Γ2, and the energy transfer has a rate κ. In some embodiments, the absolute value of the difference of the angular frequencies ω1 and ω2 is smaller than the broader of the resonant widths Γ1 and Γ2.
  • In some embodiments, the coupling to loss ratio
  • κ Γ 1 Γ 2 > 0.5 , κ Γ 1 Γ 2 > 1 , κ Γ 1 Γ 2 > 2 , or κ Γ 1 Γ 2 > 5.
  • In some such embodiments, D/L2 may be as large as 2, as large as 3, as large as 5, as large as 7, or as large as 10.
  • It is to be understood that the characteristic size of an object is equal to the radius of the smallest sphere which can fit around the entire object. The characteristic thickness of an object is, when placed on a flat surface in any arbitrary configuration, the smallest possible height of the highest point of the object above a flat surface. The characteristic width of an object is the radius of the smallest possible circle that the object can pass through while traveling in a straight line. For example, the characteristic width of a cylindrical object is the radius of the cylinder.
  • The distance D over which the energy transfer between two resonant objects occurs is the distance between the respective centers of the smallest spheres which can fit around the entirety of each object. However, when considering the distance between a human and a resonant object, the distance is to be measured from the outer surface of the human to the outer surface of the sphere.
  • As described in detail below, non-radiative energy transfer refers to energy transfer effected primarily through the localized near field, and, at most, secondarily through the radiative portion of the field.
  • It is to be understood that an evanescent tail of a resonant object is the decaying non-radiative portion of a resonant field localized at the object. The decay may take any functional form including, for example, an exponential decay or power law decay.
  • The optimum efficiency frequency of a wireless energy transfer system is the frequency at which the figure of merit
  • κ Γ 1 Γ 2
  • is maximized, all other factors held constant.
  • The resonant width (Γ) refers to the width of an object's resonance due to object's intrinsic losses (e.g. loss to absorption, radiation, etc.).
  • It is to be understood that a Q-factor (Q) is a factor that compares the time constant for decay of an oscillating system's amplitude to its oscillation period. For a given resonator mode with angular frequency ωand resonant width Γ, the Q-factor Q=ω/2Γ.
  • The energy transfer rate (κ) refers to the rate of energy transfer from one resonator to another. In the coupled mode description described below it is the coupling constant between the resonators.
  • It is to be understood that Qκ=ω/2κ.
  • Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict with publications, patent applications, patents, and other references mentioned incorporated herein by reference, the present specification, including definitions, will control.
  • Various embodiments may include any of the above features, alone or in combination. Other features, objects, and advantages of the disclosure will be apparent from the following detailed description.
  • Other features, objects, and advantages of the disclosure will be apparent from the following detailed description.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • FIG. 1 shows a schematic of a wireless energy transfer scheme.
  • FIG. 2 shows an example of a self-resonant conducting-wire coil.
  • FIG. 3 shows a wireless energy transfer scheme featuring two self-resonant conducting-wire coils
  • FIG. 4 shows an example of a capacitively loaded conducting-wire coil, and illustrates the surrounding field.
  • FIG. 5 shows a wireless energy transfer scheme featuring two capacitively loaded conducting-wire coils, and illustrates the surrounding field.
  • FIG. 6 shows an example of a resonant dielectric disk, and illustrates the surrounding field.
  • FIG. 7 shows a wireless energy transfer scheme featuring two resonant dielectric disks, and illustrates the surrounding field.
  • FIGS. 8 a and 8 b show schematics for frequency control mechanisms.
  • FIGS. 9 a through 9 c illustrate a wireless energy transfer scheme in the presence of various extraneous objects.
  • FIG. 10 illustrates a circuit model for wireless energy transfer.
  • FIG. 11 illustrates the efficiency of a wireless energy transfer scheme.
  • FIG. 12 illustrates parametric dependences of a wireless energy transfer scheme. The figure shows efficiency, total (loaded) device Q, and source and device currents, voltages and radiated powers, normalized to 1 Watt of output working power, as functions of frequency for a particular choice of source and device loop dimensions, wp and Ns and different choices of Nd=1,2,3,4,5,6,10.
  • FIG. 13 plots the parametric dependences of a wireless energy transfer scheme. Efficiency, total (loaded device Q, and source and device currents, voltages and radiated powers (normalized to 1 Watt of output working power) as functions of frequency and wp for a particular choice of source and device loop dimensions, and number of turns Ns and Nd.
  • FIG. 14 is a schematic of an experimental system demonstrating wireless energy transfer.
  • FIGS. 15-17. Plot experiment results for the system shown schematically in FIG. 14. FIG. 15 shows a comparison of experimental and theoretical values for κ as a function of the separation between the source and device coils. FIG. 16 shows a comparison of experimental and theoretical values for the parameter κ/Γ as a function of the separation between the two coils. The theory values are obtained by using the theoretically obtained κ and the experimentally measured Γ. The shaded area represents the spread in the theoretical κ/Γ due to the ˜5% uncertainty in Q.
  • DETAILED DESCRIPTION
  • FIG. 1 shows a schematic that generally describes one embodiment of the invention, in which energy is transferred wirelessly between two resonant objects.
  • Referring to FIG. 1, energy is transferred, over a distance D, between a resonant source object having a characteristic size L1 and a resonant device object of characteristic size L2. Both objects are resonant objects. The source object is connected to a power supply (not shown), and the device object is connected to a power consuming device (e.g. a load resistor, not shown). Energy is provided by the power supply to the source object, transferred wirelessly and non-radiatively from the source object to the device object, and consumed by the power consuming device. The wireless non-radiative energy transfer is performed using the field (e.g. the electromagnetic field or acoustic field) of the system of two resonant objects. For simplicity, in the following we will assume that field is the electromagnetic field.
  • It is to be understood that while two resonant objects are shown in the embodiment of FIG. 1, and in many of the examples below, other embodiments may feature 3 or more resonant objects. For example, in some embodiments a single source object can transfer energy to multiple device objects. In some embodiments energy may be transferred from a first device to a second, and then from the second device to the third, and so forth.
  • Initially, we present a theoretical framework for understanding non-radiative wireless energy transfer. Note however that it is to be understood that the scope of the invention is not bound by theory.
  • Coupled Mode Theory
  • An appropriate analytical framework for modeling the resonant energy-exchange between two resonant objects 1 and 2 is that of “coupled-mode theory” (CMT). The field of the system of two resonant objects 1 and 2 is approximated by F(r,t)≈a1(t)F1(r)+a2(t)F2(r), where F1,2(r) are the eigenmodes of 1 and 2 alone, normalized to unity energy, and the field amplitudes a1,2(t) are defined so that |a1,2(t)|2is equal to the energy stored inside the objects 1 and 2 respectively. Then, the field amplitudes can be shown to satisfy, to lowest order:
  • a 1 t = - i ( ω 1 i Γ 1 ) a 1 + i κ a 2 a 2 t = - i ( ω 2 - i Γ 2 ) a 2 + i κ a 1 , ( 1 )
  • where ω1,2 are the individual angular eigenfrequencies of the eigenmodes, Γ1,2 are the resonance widths due to the objects' intrinsic (absorption, radiation etc.) losses, and κ is the coupling coefficient. Eqs.(1) show that at exact resonance (ω12 and Γ12), the eigenmodes of the combined system are split by 2κ; the energy exchange between the two objects takes place in time ˜π/2κ and is nearly perfect, apart for losses, which are minimal when the coupling rate is much faster than all loss rates (κ
    Figure US20100253152A1-20101007-P00003
    Γ1,2). The coupling to loss ratio κ/√{square root over (Γ1Γ2)} serves as a figure-of-merit in evaluating a system used for wireless energy-transfer, along with the distance over which this ratio can be achieved. The regime κ√{square root over (Γ1Γ2)}
    Figure US20100253152A1-20101007-P00001
    1 is called “strong-coupling” regime.
  • In some embodiments, the energy-transfer application preferably uses resonant modes of high Q=ω/2Γ, corresponding to low (i.e. slow) intrinsic-loss rates Γ. This condition may be satisfied where the coupling is implemented using, not the lossy radiative far-field, but the evanescent (non-lossy) stationary near-field.
  • To implement an energy-transfer scheme, usually finite objects, namely ones that are topologically surrounded everywhere by air, are more appropriate. Unfortunately, objects of finite extent cannot support electromagnetic states that are exponentially decaying in all directions in air, since, from Maxwell's Equations in free space: {right arrow over (k)}22/c2 where κ is the wave vector, co the angular frequency, and c the speed of light. Because of this, one can show that they cannot support states of infinite Q. However, very long-lived (so-called “high-Q”) states can be found, whose tails display the needed exponential or exponential-like decay away from the resonant object over long enough distances before they turn oscillatory (radiative). The limiting surface, where this change in the field behavior happens, is called the “radiation caustic”, and, for the wireless energy-transfer scheme to be based on the near field rather than the far/radiation field, the distance between the coupled objects must be such that one lies within the radiation caustic of the other.
  • Furthermore, in some embodiments, small Qκ=ω/2κ corresponding to strong (i.e. fast) coupling rate κ is preferred over distances larger than the characteristic sizes of the objects. Therefore, since the extent of the near-field into the area surrounding a finite-sized resonant object is set typically by the wavelength, in some embodiments, this mid-range non-radiative coupling can be achieved using resonant objects of subwavelength size, and thus significantly longer evanescent field-tails. As will be seen in examples later on, such subwavelength resonances can often be accompanied with a high Q, so this will typically be the appropriate choice for the possibly-mobile resonant device-object. Note, though, that in some embodiments, the resonant source-object will be immobile and thus less restricted in its allowed geometry and size, which can be therefore chosen large enough that the near-field extent is not limited by the wavelength. Objects of nearly infinite extent, such as dielectric waveguides, can support guided modes whose evanescent tails are decaying exponentially in the direction away from the object, slowly if tuned close to cutoff, and can have nearly infinite Q.
  • In the following, we describe several examples of systems suitable for energy transfer of the type described above. We will demonstrate how to compute the CMT parameters ω1,2, Q1,2 and Qκ described above and how to choose these parameters for particular embodiments in order to produce a desirable figure-of-merit κ/√{square root over (Γ1Γ2)}=√{square root over (Q1Q2)}/Qκ. In particular, this figure of merit is typically maximized when ω1,2 are tuned to a particular angular frequency {tilde over (ω)}, thus, if {tilde over (Γ)} is half the angular-frequency width for which √{right arrow over (Q1Q2)}/Qκ is above half its maximum value at {tilde over (ω)}, the angular eigenfrequencies ω1,2 should typically be tuned to be close to {tilde over (ω)} to within the width {tilde over (Γ)}.
  • In addition, as described below, Q1,2 can sometimes be limited not from intrinsic loss mechanisms but from external perturbations. In those cases, producing a desirable figure-of-merit translates to reducing Qκ (i.e. increasing the coupling). Accordingly we will demonstrate how, for particular embodiments, to reduce Qκ.
  • Self-Resonant Conducting Coils
  • In some embodiments, one or more of the resonant objects are self-resonant conducting coils. Referring to FIG. 2, a conducting wire of length l and cross-sectional radius a is wound into a helical coil of radius r and height h (namely with N=√{square root over (l2−h2)}/2πr number of turns), surrounded by air. As described below, the wire has distributed inductance and distributed capacitance, and therefore it supports a resonant mode of angular frequency ω. The nature of the resonance lies in the periodic exchange of energy from the electric field within the capacitance of the coil, due to the charge distribution Σ(x) across it, to the magnetic field in free space, due to the current distribution j(x) in the wire. In particular, the charge conservation equation ∇·j=iωρ implies that: (i) this periodic exchange is accompanied by a π/2 phase-shift between the current and the charge density profiles, namely the energy U contained in the coil is at certain points in time completely due to the current and at other points in time completely due to the charge, and (ii) if ρ1(x) and I(x) are respectively the linear charge and current densities in the wire, where x runs along the wire,
  • q o = 1 2 x ρ l ( x )
  • is the maximum amount of positive charge accumulated in one side of the coil (where an equal amount of negative charge always also accumulates in the other side to make the system neutral) and Io=max{|I(x)|} is the maximum positive value of the linear current distribution, then Io=ωqo. Then, one can define an effective total inductance L and an effective total capacitance C of the coil through the amount of energy U inside its resonant mode:
  • U 1 2 I o 2 L L = μ o 4 π I o 2 x x j ( x ) · j ( x ) x - x , ( 2 ) U 1 2 q o 2 1 C 1 C = 1 4 πɛ o q o 2 x x ρ ( x ) · ρ ( x ) x - x , ( 3 )
  • where μO and εO, are the magnetic permeability and electric permittivity of free space. With these definitions, the resonant angular frequency and the effective impedance are given by the common formulas ω=1/√{square root over (LC)} and Z={square root over (L/C)} respectively.
  • Losses in this resonant system consist of ohmic (material absorption) loss inside the wire and radiative loss into free space. One can again define a total absorption resistance Rabs from the amount of power absorbed inside the wire and a total radiation resistance Rrad from the amount of power radiated due to electric- and magnetic-dipole radiation:
  • P abs 1 2 I o 2 R abs R abs ζ c l 2 π a · I rms 2 I o 2 ( 4 ) P rad 1 2 I o 2 R rad R rad ζ o 6 π [ ( ω p c ) 2 + ( ω m c ) 4 ] , ( 5 )
  • where c=1/√{square root over (μoεo)} and ζO={square root over (μOO)} are the light velocity and light impedance in free space, the impedance ζc is ζc=1/σδ=√{square root over (μoω/2σ)} with σ the conductivity of the conductor and δ the skin depth at the frequency ω,
  • I rms 2 = 1 l x I ( x ) 2 ,
  • p=∫dx rρl(x) is the electric-dipole moment of the coil and
  • m = 1 2 x r × j ( x )
  • is the magnetic-dipole moment of the coil. For the radiation resistance formula Eq.(5), the assumption of operation in the quasi-static regime (h,r
    Figure US20100253152A1-20101007-P00004
    2πc/ω) has been used, which is the desired regime of a subwavelength resonance. With these definitions, the absorption and radiation quality factors of the resonance are given by Qabs=Z/Rabs and Qrad =Z/Rrad respectively.
  • From Eq.(2)-(5) it follows that to determine the resonance parameters one simply needs to know the current distribution j in the resonant coil. Solving Maxwell's equations to rigorously find the current distribution of the resonant electromagnetic eigenmode of a conducting-wire coil is more involved than, for example, of a standard LC circuit, and we can find no exact solutions in the literature for coils of finite length, making an exact solution difficult. One could in principle write down an elaborate transmission-line-like model, and solve it by brute force. We instead present a model that is (as described below) in good agreement (˜5%) with experiment. Observing that the finite extent of the conductor forming each coil imposes the boundary condition that the current has to be zero at the ends of the coil, since no current can leave the wire, we assume that the resonant mode of each coil is well approximated by a sinusoidal current profile along the length of the conducting wire. We shall be interested in the lowest mode, so if we denote by x the coordinate along the conductor, such that it runs from −l/2 to +l/2, then the current amplitude profile would have the form I(x)=I0 cos(πx/l), where we have assumed that the current does not vary significantly along the wire circumference for a particular x, a valid assumption provided a
    Figure US20100253152A1-20101007-P00004
    r. It immediately follows from the continuity equation for charge that the linear charge density profile should be of the form ρ1(x)=ρo sin(πx/l), and thus qo=∫0 l/2 dxρo|sin(πx/l)|=ρol/π. Using these sinusoidal profiles we find the so-called “self-inductance” Ls and “self-capacitance” Cs of the coil by computing numerically the integrals Eq.(2) and (3); the associated frequency and effective impedance are ωs and Zs respectively. The “self-resistances” R, are given analytically by Eq.(4) and (5) using
  • I rms 2 = 1 l - 1 / 2 1 / 2 x I o cos ( π x / l ) 2 = 1 2 I o 2 , p = q o ( 2 π h ) 2 + ( 4 N cos ( π N ) ( 4 N 2 - 1 ) π r ) 2 and m = I o ( 2 π N π r 2 ) 2 + ( cos ( π N ) ( 12 N 2 - 1 ) - sin ( π N ) π N ( 4 N 2 - 1 ) ( 16 N 4 - 8 N 2 + 1 ) π hr ) 2 ,
  • and therefore the associated Qs factors may be calculated.
  • The results for two particular embodiments of resonant coils with subwavelength modes of λsr>70 (i.e. those highly suitable for near-field coupling and well within the quasi-static limit) are presented in Table 1. Numerical results are shown for the wavelength and absorption, radiation and total loss rates, for the two different cases of subwavelength-coil resonant modes. Note that, for conducting material, copper (σ=5.998·10̂-7 S/m) was used. It can be seen that expected quality factors at microwave frequencies are Qs abs≧1000 and Qs rad≧5000.
  • TABLE 1
    single coil λs/r f(MHz) Qs rad Qs abs Qs = ωs/2Γs
    r = 30 cm, h = 20 cm, 74.7 13.39 4164 8170 2758
    a = 1 cm, N = 4
    r = 10 cm, h = 3 cm, 140 21.38 43919 3968 3639
    a = 2 mm, N = 6
  • Referring to FIG. 3, in some embodiments, energy is transferred between two self-resonant conducting-wire coils. The electric and magnetic fields are used to couple the different resonant conducting-wire coils at a distance D between their centers. Usually, the electric coupling highly dominates over the magnetic coupling in the system under consideration for coils with h
    Figure US20100253152A1-20101007-P00001
    2r and, oppositely, the magnetic coupling highly dominates over the electric coupling for coils with h
    Figure US20100253152A1-20101007-P00004
    2r . Defining the charge and current distributions of two coils 1,2 respectively as ρ1,2(x) and j1,2(x), total charges and peak currents respectively as q1,2 and I1,2, and capacitances and inductances respectively as C1,2 and L1,2, which are the analogs of ρ(x), j(x), qo, Io, C and L for the single-coil case and are therefore well defined, we can define their mutual capacitance and inductance through the total energy:
  • U U 1 + U 2 + 1 2 ( q 1 * q 2 + q 2 * q 1 ) / M C + 1 2 ( I 1 * I 2 + I 2 * I 1 ) M L 1 / M C = 1 4 πɛ o q 1 q 2 x x ρ 1 ( x ) · ρ 2 ( x ) x - x u , M L = μ o 4 π I 1 I 2 x x j 1 ( x ) · j 2 ( x ) x - x u , where U 1 = 1 2 q 1 2 / C 1 = 1 2 I 1 2 L 1 , U 2 = 1 2 q 2 2 / C 2 = 1 2 I 2 2 L 2 ( 6 )
  • and the retardation factor of u=exp(iω|x−x′|/c) inside the integral can been ignored in the quasi-static regime D
    Figure US20100253152A1-20101007-P00004
    λ of interest, where each coil is within the near field of the other. With this definition, the coupling coefficient is given by κ=ω√{square root over (C1C2)}/2MC+ωML/2√{square root over (L1L2)}
    Figure US20100253152A1-20101007-P00005
    Qκ −1=(MC/√{square root over (C1C2)})−1+(√{square root over (L1L2)}/ML)−1.
  • Therefore, to calculate the coupling rate between two self-resonant coils, again the current profiles are needed and, by using again the assumed sinusoidal current profiles, we compute numerically from Eq.(6) the mutual capacitance MC,s and inductance ML,s between two self-resonant coils at a distance D between their centers, and thus Qκ,s is also determined.
  • TABLE 2
    pair of coils D/r Q = ω/2Γ Qκ = ω/2κ κ/Γ
    r = 30 cm, h = 20 cm, 3 2758 38.9 70.9
    a = 1 cm, N = 4 5 2758 139.4 19.8
    λ/r ≈ 75 7 2758 333.0 8.3
    Qs abs ≈ 8170, Qs rad ≈ 4164 10 2758 818.9 3.4
    r = 10 cm, h = 3 cm, 3 3639 61.4 59.3
    a = 2 mm, N = 6 5 3639 232.5 15.7
    λ/r ≈ 140 7 3639 587.5 6.2
    Qs abs ≈ 3968, Qs rad ≈ 43919 10 3639 1580 2.3
  • Referring to Table 2, relevant parameters are shown for exemplary embodiments featuring pairs or identical self resonant coils. Numerical results are presented for the average wavelength and loss rates of the two normal modes (individual values not shown), and also the coupling rate and figure-of-merit as a function of the coupling distance D, for the two cases of modes presented in Table 1. It can be seen that for medium distances D/r=10−3 the expected coupling-to-loss ratios are in the range κ/Γ˜2-70.
  • Capacitively-Loaded Conducting Loops or Coils
  • In some embodiments, one or more of the resonant objects are capacitively-loaded conducting loops or coils. Referring to FIG. 4 a helical coil with N turns of conducting wire, as described above, is connected to a pair of conducting parallel plates of area A spaced by distance d via a dielectric material of relative permittivity ε, and everything is surrounded by air (as shown, N=l and h=0). The plates have a capacitance CpoεA/d , which is added to the distributed capacitance of the coil and thus modifies its resonance. Note however, that the presence of the loading capacitor modifies significantly the current distribution inside the wire and therefore the total effective inductance L and total effective capacitance C of the coil are different respectively from Ls and Cs, which are calculated for a self-resonant coil of the same geometry using a sinusoidal current profile. Since some charge is accumulated at the plates of the external loading capacitor, the charge distribution p inside the wire is reduced, so C<Cs, and thus, from the charge conservation equation, the current distribution j flattens out, so L>Ls. The resonant frequency for this system is ω=1/√{square root over (L(C+Cp))}<ωs=1/√{square root over (LsCs)}, and I(x)→Io cos(πx/l)
    Figure US20100253152A1-20101007-P00006
    C→Cs
    Figure US20100253152A1-20101007-P00006
    ω→ωs, as Cp→0.
  • In general, the desired CMT parameters can be found for this system, but again a very complicated solution of Maxwell's Equations is required. Instead, we will analyze only a special case, where a reasonable guess for the current distribution can be made. When Cp
    Figure US20100253152A1-20101007-P00001
    Cs>C, then ω≈1/√{square root over (LCp)}
    Figure US20100253152A1-20101007-P00004
    ωs and Z≈√{square root over (L/Cp)}
    Figure US20100253152A1-20101007-P00004
    Zs, while all the charge is on the plates of the loading capacitor and thus the current distribution is constant along the wire. This allows us now to compute numerically L from Eq.(2). In the case h=0 and N integer, the integral in Eq.(2) can actually be computed analytically, giving the formula L=μor[ln(8r/a)−2]N2. Explicit analytical formulas are again available for R from Eq.(4) and (5), since Irms=Io, |p|≈0 and |m|=IoNπr2 (namely only the magnetic-dipole term is contributing to radiation), so we can determine also Qabs=ωL/Rabs and Qrad=ωL/Rrad. At the end of the calculations, the validity of the assumption of constant current profile is confirmed by checking that indeed the condition Cp
    Figure US20100253152A1-20101007-P00001
    Cs
    Figure US20100253152A1-20101007-P00005
    ω
    Figure US20100253152A1-20101007-P00004
    ωs is satisfied. To satisfy this condition, one could use a large external capacitance, however, this would usually shift the operational frequency lower than the optimal frequency, which we will determine shortly; instead, in typical embodiments, one often prefers coils with very small self-capacitance Cs to begin with, which usually holds, for the types of coils under consideration, when N=1, so that the self-capacitance comes from the charge distribution across the single turn, which is almost always very small, or when N>1 and h
    Figure US20100253152A1-20101007-P00001
    2Na , so that the dominant self-capacitance comes from the charge distribution across adjacent turns, which is small if the separation between adjacent turns is large.
  • The external loading capacitance Cp provides the freedom to tune the resonant frequency (for example by tuning A or d). Then, for the particular simple case h=0, for which we have analytical formulas, the total Q=ωL/(Rabs Rrad) becomes highest at the optimal frequency
  • ω ~ = [ c 4 π ɛ o 2 σ · 1 a Nr 3 ] 2 / 7 , ( 7 )
  • reaching the value
  • Q ~ = 6 7 π ( 2 π 2 η o σ a 2 N 2 r ) 3 / 7 · [ ln ( 8 r a ) - 2 ] . ( 8 )
  • At lower frequencies it is dominated by ohmic loss and at higher frequencies by radiation. Note, however, that the formulas above are accurate as long as {tilde over (ω)}
    Figure US20100253152A1-20101007-P00004
    ωs and, as explained above, this holds almost always when N=1, and is usually less accurate when N>1, since h=0 usually implies a large self-capacitance. A coil with large h can be used, if the self-capacitance needs to be reduced compared to the external capacitance, but then the formulas for L and {tilde over (ω)}, {tilde over (Q)} are again less accurate. Similar qualitative behavior is expected, but a more complicated theoretical model is needed for making quantitative predictions in that case.
  • The results of the above analysis for two embodiments of subwavelength modes of λ/r≧70 (namely highly suitable for near-field coupling and well within the quasi-static limit) of coils with N=1 and h=0 at the optimal frequency Eq.(7) are presented in Table 3. To confirm the validity of constant-current assumption and the resulting analytical formulas, mode-solving calculations were also performed using another completely independent method: computational 3D finite-element frequency-domain (FEFD) simulations (which solve Maxwell's Equations in frequency domain exactly apart for spatial discretization) were conducted, in which the boundaries of the conductor were modeled using a complex impedance ζ=√{square root over (μoω/2σ)} boundary condition, valid as long as 70 co
    Figure US20100253152A1-20101007-P00004
    1 (10−5 for copper in the microwave). Table 3 shows Numerical FEFD (and in parentheses analytical) results for the wavelength and absorption, radiation and total loss rates, for two different cases of subwavelength-loop resonant modes. Note that for conducting material copper (σ=5.998·107 S/m) was used. (The specific parameters of the plot in FIG. 4 are highlighted with bold in the table.) The two methods (analytical and computational) are in very good agreement and show that, in some embodiments, the optimal frequency is in the low-MHz microwave range and the expected quality factors are Qabs≧1000 and Qrad≧10000.
  • TABLE 3
    single coil λ/r f(MHz) Qrad Qabs Q = ω/2Γ
    r = 30 cm, a = 2 cm 111.4 (112.4) 8.976 (8.897) 29546 (30512) 4886 (5117) 4193 (4381)
    ε = 10, A = 138 cm2, d = 4 mm
    r = 10 cm, a = 2 mm 69.7 (70.4) 43.04 (42.61) 10702 (10727) 1545 (1604) 1350 (1395)
    ε = 10, A = 3.14 cm2, d = 1 mm
  • Referring to FIG. 5, in some embodiments, energy is transferred between two capacitively-loaded coils. For the rate of energy transfer between two capacitively-loaded coils 1 and 2 at distance D between their centers, the mutual inductance ML can be evaluated numerically from Eq.(6) by using constant current distributions in the case ω
    Figure US20100253152A1-20101007-P00004
    ωs. In the case h=0, the coupling is only magnetic and again we have an analytical formula, which, in the quasi-static limit r
    Figure US20100253152A1-20101007-P00002
    D
    Figure US20100253152A1-20101007-P00002
    λ and for the relative orientation shown in FIG. 4, is ML≈πμ/2·(r1r2)2N1N2/D3, which means that Qκ∝(D/√{square root over (r1 2)})3 is independent of the frequency a) and the number of turns N1, N2. Consequently, the resultant coupling figure-of-merit of interest is
  • κ Γ 1 Γ 2 = Q 1 Q 2 Q κ ( r 1 r 2 D ) 3 · π 2 η o r 1 r 2 λ · N 1 N 2 j = 1 , 2 ( πη o λσ · r j a j N j + 8 3 π 5 η o ( r j λ ) 4 N j 2 ) 1 / 2 , ( 9 )
  • which again is more accurate for N1=N2=1.
  • From Eq.(9) it can be seen that the optimal frequency {tilde over (ω)}, where the figure-of-merit is maximized to the value {tilde over (()}{tilde over (Q)}{tilde over ((Q1Q2)}/Qκ), is that where √{square root over (Q1Q2)} is maximized, since Qκ does not depend on frequency (at least for the distances D<<λ of interest for which the quasi-static approximation is still valid). Therefore, the optimal frequency is independent of the distance D between the two coils and lies between the two frequencies where the single-coil Q1 and Q2 peak. For same coils, it is given by Eq.(7) and then the figure-of-merit Eq.(9) becomes
  • ( κ Γ ) = Q ~ Q κ ( r D ) 3 · 3 7 ( 2 π 2 η o σ a 2 N 2 r ) 3 / 7 . ( 10 )
  • Typically, one should tune the capacitively-loaded conducting loops or coils, so that their angular eigenfrequencies are close to {tilde over (ω)}within {tilde over (β)} which is half the angular frequency width for which √{square root over (Q1Q2)}/Qκ>{tilde over (()}{tilde over (Q)}{tilde over ((Q1Q2/Qκ)/2)}.
  • Referring to Table 4, numerical FEFD and, in parentheses, analytical results based on the above are shown for two systems each composed of a matched pair of the loaded coils described in Table 3. The average wavelength and loss rates are shown along with the coupling rate and coupling to loss ratio figure-of-merit κ/Γ as a function of the coupling distance D, for the two cases. Note that the average numerical Γrad shown are again slightly different from the single-loop value of FIG. 3, analytical results for Γrad are not shown but the single-loop value is used. (The specific parameters corresponding to the plot in FIG. 5 are highlighted with bold in the table.) Again we chose N=1 to make the constant-current assumption a good one and computed ML numerically from Eq.(6). Indeed the accuracy can be confirmed by their agreement with the computational FEFD mode-solver simulations, which give κ through the frequency splitting (=2κ) of the two normal modes of the combined system. The results show that for medium distances D/r=10−3 the expected coupling-to-loss ratios are in the range κ/Γ0.5-50.
  • TABLE 4
    pair of coils D/r Qrad Q = ω/2Γ Qκ = ω/2κ κ/Γ
    r = 30 cm, a = 2 cm 3 30729 4216 62.6 (63.7) 67.4 (68.7)
    ε = 10, A = 138 cm2, d = 4 mm 5 29577 4194 235 (248) 17.8 (17.6)
    λ/r ≈ 112 7 29128 4185 589 (646) 7.1 (6.8)
    Qabs ≈ 4886 10 28833 4177 1539 (1828) 2.7 (2.4)
    r = 10 cm, a = 2 mm 3 10955 1355 85.4 (91.3) 15.9 (15.3)
    ε = 10, A = 3.14 cm2, d = 1 mm 5 10740 1351 313 (356) 4.32 (3.92)
    λ/r ≈ 70 7 10759 1351 754 (925) 1.79 (1.51)
    Qabs ≈ 1546 10 10756 1351 1895 (2617) 0.71 (0.53)
  • Optimization of √{square root over (Q1Q2)}/Qκ
  • In some embodiments, the results above can be used to increase or optimize the performance of a wireless energy transfer system which employs capacitively-loaded coils. For example, the scaling of Eq.(10) with the different system parameters one sees that to maximize the system figure-of-merit κ/Γ one can, for example:
      • Decrease the resistivity of the conducting material. This can be achieved, for example, by using good conductors (such as copper or silver) and/or lowering the temperature. At very low temperatures one could use also superconducting materials to achieve extremely good performance.
      • Increase the wire radius a. In typical embodiments, this action is limited by physical size considerations. The purpose of this action is mainly to reduce the resistive losses in the wire by increasing the cross-sectional area through which the electric current is flowing, so one could alternatively use also a Litz wire or a ribbon instead of a circular wire.
      • For fixed desired distance D of energy transfer, increase the radius of the loop r. In typical embodiments, this action is limited by physical size considerations.
      • For fixed desired distance vs. loop-size ratio D/r, decrease the radius of the loop r. In typical embodiments, this action is limited by physical size considerations.
      • Increase the number of turns N. (Even though Eq.(10) is expected to be less accurate for N>1, qualitatively it still provides a good indication that we expect an improvement in the coupling-to-loss ratio with increased N.) In typical embodiments, this action is limited by physical size and possible voltage considerations, as will be discussed in following sections.
      • Adjust the alignment and orientation between the two coils. The figure-of-merit is optimized when both cylindrical coils have exactly the same axis of cylindrical symmetry (namely they are “facing” each other). In some embodiments, particular mutual coil angles and orientations that lead to zero mutual inductance (such as the orientation where the axes of the two coils are perpendicular) should be avoided.
      • Finally, note that the height of the coil h is another available design parameter, which has an impact to the performance similar to that of its radius r, and thus the design rules are similar.
  • The above analysis technique can be used to design systems with desired parameters. For example, as listed below, the above described techniques can be used to determine the cross sectional radius a of the wire which one should use when designing as system two same single-turn loops with a given radius in order to achieve a specific performance in terms of κ/Γ at a given D/r between them, when the material is copper (σ=5.998·107 S/m):
      • D/r=5, κ/Γ≧10, r=30 cm
        Figure US20100253152A1-20101007-P00006
        α≧9 mm
      • D/r=5, κ/Γ≧10, r=5 cm
        Figure US20100253152A1-20101007-P00006
        α≧3.7 mm
      • D/r=5, κ/Γ≧20, r=30 cm
        Figure US20100253152A1-20101007-P00006
        α≧20 mm
      • D/r=5, κ/Γ≧20, r=5 cm
        Figure US20100253152A1-20101007-P00006
        α≧8.3 mm
      • D/r=10, κ/Γ≧1, r=30 cm
        Figure US20100253152A1-20101007-P00006
        α≧7 mm
      • D/r=10, κ/Γ≧1, r=5 cm
        Figure US20100253152A1-20101007-P00006
        α≧2.8 mm
      • D/r=10, κ/Γ≧3, r=30 cm
        Figure US20100253152A1-20101007-P00006
        α≧20 mm
      • D/r=10, κ/Γ>20, r=5 cm
        Figure US20100253152A1-20101007-P00006
        α≧10 mm
  • Similar analysis can be done for the case of two dissimilar loops. For example, in some embodiments, the device under consideration is very specific (e.g. a laptop or a cell phone), so the dimensions of the device object (rd,hd,ad,Nd) are very restricted. However, in some such embodiments, the restrictions on the source object rs,hssNs) are much less, since the source can, for example, be placed under the floor or on the ceiling. In such cases, the desired distance is often well defined, based on the application (e.g. D˜1 m for charging a laptop on a table wirelessly from the floor). Listed below are examples (simplified to the case Ns=Nd=1 and hs=hd=0) of how one can vary the dimensions of the source object to achieve the desired system performance in terms of κ/√{square root over (ΓsΓd)}, when the material is again copper (σ=5.998·107 S/m):
  • D=1.5 m, κ/√{square root over (ΓsΓd)}≧15, rd=30 cm, αd=6 mm
    Figure US20100253152A1-20101007-P00006
    rs=1.158 m, αs≧5 mm
  • D=1.5 m, κ/√{square root over (ΓsΓd)}≧30, rd=30 cm, αd=6 mm
    Figure US20100253152A1-20101007-P00006
    rs=1.15 m, αs≧33 mm
  • D=1.5 m, κ/√{square root over (ΓsΓd)}≧1, rd=5 cm, αd=4 mm
    Figure US20100253152A1-20101007-P00006
    rs=1.119 m, αs≧7 mm
  • D=1.5 m, κ/√{square root over (ΓsΓd)}≧2, rd=5 cm, αd=4 mm
    Figure US20100253152A1-20101007-P00006
    rs=1.119 m, αs≧52 mm
  • D=2 m, κ/√{square root over (ΓsΓd)}≧10, rd=30 cm, αd=6 mm
    Figure US20100253152A1-20101007-P00006
    rs=1.518 m, αs≧7 mm
  • D=2 m, κ/√{square root over (ΓsΓd)}≧20, rd=30 cm, αd=6 mm
    Figure US20100253152A1-20101007-P00006
    rs=1.514 m, αs≧50 mm
  • D=2 m, κ/√{square root over (ΓsΓd)}≧0.5, rd=5 cm, αd=4 mm
    Figure US20100253152A1-20101007-P00006
    rs=1.491 m, αs≧5 mm
  • D=2 m, κ/√{square root over (ΓsΓd)}≧1, rd=5 cm, αd=4 mm
    Figure US20100253152A1-20101007-P00006
    rs=1.491 m, αs≧36 mm
  • Optimization of Qκ
  • As will be described below, in some embodiments the quality factor Q of the resonant objects is limited from external perturbations and thus varying the coil parameters cannot lead to improvement in Q. In such cases, one may opt to increase the coupling to loss ratio figure-of-merit by decreasing Qκ (i.e. increasing the coupling). The coupling does not depend on the frequency and the number of turns. Therefore, the remaining degrees of freedom are:
      • Increase the wire radii a1 and a2. In typical embodiments, this action is limited by physical size considerations.
      • For fixed desired distance D of energy transfer, increase the radii of the coils r1 and r2. In typical embodiments, this action is limited by physical size considerations.
      • For fixed desired distance vs. coil-sizes ratio D/√{square root over (r1r2)}, only the weak (logarithmic) dependence of the inductance remains, which suggests that one should decrease the radii of the coils r1 and r2. In typical embodiments, this action is limited by physical size considerations.
      • Adjust the alignment and orientation between the two coils. In typical embodiments, the coupling is optimized when both cylindrical coils have exactly the same axis of cylindrical symmetry (namely they are “facing” each other). Particular mutual coil angles and orientations that lead to zero mutual inductance (such as the orientation where the axes of the two coils are perpendicular) should obviously be avoided.
      • Finally, note that the heights of the coils h1 and h2 are other available design parameters, which have an impact to the coupling similar to that of their radii r1 and r2, and thus the design rules are similar.
  • Further practical considerations apart from efficiency, e.g. physical size limitations, will be discussed in detail below.
  • It is also important to appreciate the difference between the above described resonant-coupling inductive scheme and the well-known non-resonant inductive scheme for energy transfer. Using CMT it is easy to show that, keeping the geometry and the energy stored at the source fixed, the resonant inductive mechanism allows for ˜Q2 (˜106) times more power delivered for work at the device than the traditional non-resonant mechanism. This is why only close-range contact-less medium-power (˜W) transfer is possible with the latter, while with resonance either close-range but large-power (˜kW) transfer is allowed or, as currently proposed, if one also ensures operation in the strongly-coupled regime, medium-range and medium-power transfer is possible. Capacitively-loaded conducting loops are currently used as resonant antennas (for example in cell phones), but those operate in the far-field regime with D/r
    Figure US20100253152A1-20101007-P00003
    1, r/λ˜1, and the radiation Q's are intentionally designed to be small to make the antenna efficient, so they are not appropriate for energy transfer.
  • Inductively-Loaded Conducting Rods
  • A straight conducting rod of length 2h and cross-sectional radius a has distributed capacitance and distributed inductance, and therefore it supports a resonant mode of angular frequency ω. Using the same procedure as in the case of self-resonant coils, one can define an effective total inductance L and an effective total capacitance C of the rod through formulas (2) and (3). With these definitions, the resonant angular frequency and the effective impedance are given again by the common formulas ω=1/√{square root over (LC)} and Z=√{square root over (L/C)} respectively. To calculate the total inductance and capacitance, one can assume again a sinusoidal current profile along the length of the conducting wire. When interested in the lowest mode, if we denote by x the coordinate along the conductor, such that it runs from −h to +h, then the current amplitude profile would have the form I(x)=Io cos(πx/2h), since it has to be zero at the open ends of the rod. This is the well-known half-wavelength electric dipole resonant mode.
  • In some embodiments, one or more of the resonant objects are inductively-loaded conducting rods. A straight conducting rod of length 2h and cross-sectional radius a, as in the previous paragraph, is cut into two equal pieces of length h, which are connected via a coil wrapped around a magnetic material of relative permeability μ, and everything is surrounded by air. The coil has an inductance Lc, which is added to the distributed inductance of the rod and thus modifies its resonance. Note however, that the presence of the center-loading inductor modifies significantly the current distribution inside the wire and therefore the total effective inductance L and total effective capacitance C of the rod are different respectively from Ls and Cs, which are calculated for a self-resonant rod of the same total length using a sinusoidal current profile, as in the previous paragraph. Since some current is running inside the coil of the external loading inductor, the current distribution j inside the rod is reduced, so L<Ls, and thus, from the charge conservation equation, the linear charge distribution ρl flattens out towards the center (being positive in one side of the rod and negative in the other side of the rod, changing abruptly through the inductor), so C>Cs. The resonant frequency for this system is ω=1/√{square root over (L+Lc)C)}<ωs=1/√{square root over (LsCs)}, and I(x)→cos(πrx/2h)
    Figure US20100253152A1-20101007-P00006
    L→Ls
    Figure US20100253152A1-20101007-P00006
    ω→ωs, as Lc→0.
  • In general, the desired CMT parameters can be found for this system, but again a very complicated solution of Maxwell's Equations is required. Instead, we will analyze only a special case, where a reasonable guess for the current distribution can be made. When Lc
    Figure US20100253152A1-20101007-P00001
    Ls>L, then ω≈1/√{square root over (LcC)}
    Figure US20100253152A1-20101007-P00004
    ωs and Z≈√{square root over (Lc/C)}
    Figure US20100253152A1-20101007-P00001
    Zs, while the current distribution is triangular along the rod (with maximum at the center-loading inductor and zero at the ends) and thus the charge distribution is positive constant on one half of the rod and equally negative constant on the other side of the rod. This allows us now to compute numerically C from Eq.(3). In this case, the integral in Eq.(3) can actually be computed analytically, giving the formula 1/C=1/(πεoh)[ln(h/a)‘1]. Explicit analytical formulas are again available for R from Eq.(4) and (5), since Irms=/o, |p|=qoh and |m|=0 (namely only the electric-dipole term is contributing to radiation), so we can determine also Qabs=1/ωCRabs and Qrad1/ωCRrad. At the end of the calculations, the validity of the assumption of triangular current profile is confirmed by checking that indeed the condition Lc
    Figure US20100253152A1-20101007-P00001
    Ls
    Figure US20100253152A1-20101007-P00005
    ω
    Figure US20100253152A1-20101007-P00004
    ωs is satisfied. This condition is relatively easily satisfied, since typically a conducting rod has very small self-inductance Ls to begin with.
  • Another important loss factor in this case is the resistive loss inside the coil of the external loading inductor Lc and it depends on the particular design of the inductor. In some embodiments, the inductor is made of a Brooks coil, which is the coil geometry which, for fixed wire length, demonstrates the highest inductance and thus quality factor. The Brooks coil geometry has NBc turns of conducting wire of cross-sectional radius aBc wrapped around a cylindrically symmetric coil former, which forms a coil with a square cross-section of side rBc, where the inner side of the square is also at radius rBc (and thus the outer side of the square is at radius 2rBc), therefore NBc(rBc/2aBc)2. The inductance of the coil is then Lc=2.0285μorBcNBc 2≈2.0285μorBc 58aBc 4 and its resistance
  • R c 1 σ l Bc π a Bc 2 1 + μ o ωσ 2 ( a Bc 2 ) 2 ,
  • where the total wire length is lBc≈2π(3rBc/2)NBc≈3πrBc 3/4aBc 2 and we have used an approximate square law for the transition of the resistance from the dc to the ac limit as the skin depth varies with frequency.
  • The external loading inductance Lc provides the freedom to tune the resonant frequency. (For example, for a Brooks coil with a fixed size rBc, the resonant frequency can be reduced by increasing the number of turns NBc by decreasing the wire cross-sectional radius aBc. Then the desired resonant angular frequency ω=1/√{square root over (LcC)} is achieved for aBc≈(2.0285μorBc 5ω2C)1/4 and the resulting coil quality factor is Qc≈0.169μoσrBc 2ω+/√{square root over (12μo√{square root over (2.0285μo(rBc/4)5C)})}). Then, for the particular simple case Lc
    Figure US20100253152A1-20101007-P00001
    Ls, for which we have analytical formulas, the total Q=1/ωC(Rc+Rabs+Rrad) becomes highest at some optimal frequency {tilde over (ω)}, reaching the value {tilde over (Q)}, both determined by the loading-inductor specific design. (For example, for the Brooks-coil procedure described above, at the optimal frequency {tilde over (Q)}≈Qc≈0.8(μoσ2 rBc 3/C)1/4) At lower frequencies it is dominated by ohmic loss inside the inductor coil and at higher frequencies by radiation. Note, again, that the above formulas are accurate as long as {tilde over (ω)}
    Figure US20100253152A1-20101007-P00004
    ωs and, as explained above, this is easy to design for by using a large inductance.
  • The results of the above analysis for two embodiments, using Brooks coils, of subwavelength modes of λ/h≧200 (namely highly suitable for near-field coupling and well within the quasi-static limit) at the optimal frequency {tilde over (ω)} are presented in Table 5. Table 5 shows in parentheses (for similarity to previous tables) analytical results for the wavelength and absorption, radiation and total loss rates, for two different cases of subwavelength-loop resonant modes. Note that for conducting material copper (σ=5.998·107 S/m) was used. The results show that, in some embodiments, the optimal frequency is in the low-MHz microwave range and the expected quality factors are Qabs≧1000 and Qrad≧100000.
  • TABLE 5
    single rod λ/h f(MHz) Qrad Qabs Q = ω/2Γ
    h = 30 cm, a = 2 cm (403.8) (2.477) (2.72*106) (7400) (7380)
    μ = 1, rBc = 2 cm, aBc = 0.88 mm, NBc = 129
    h = 10 cm, a = 2 mm (214.2) (14.010) (6.92*105) (3908) (3886)
    μ = 1, rBc = 5 mm, aBc = 0.25 mm,
  • In some embodiments, energy is transferred between two inductively-loaded rods. For the rate of energy transfer between two inductively-loaded rods 1 and 2 at distance D between their centers, the mutual capacitance Mc can be evaluated numerically from Eq.(6) by using triangular current distributions in the case ω
    Figure US20100253152A1-20101007-P00004
    ωs. In this case, the coupling is only electric and again we have an analytical formula, which, in the quasi-static limit h<<D<<λ and for the relative orientation such that the two rods are aligned on the same axis, is 1/MC≈½πεo·(h1h2)2/D3, which means that Qκ∝(D/√{square root over (h1h2)})3 is independent of the frequency co. Consequently, one can get the resultant coupling figure-of-merit of interest
  • κ Γ 1 Γ 2 = Q 1 Q 2 Q κ .
  • It can be seen that the optimal frequency {tilde over (ω)}, where the figure-of-merit is maximized to the value {tilde over (()}{tilde over (√)}{tilde over ((√{square root over (Q1/Q2)}/Qκ))}, is that where √{square root over (QqQ2)} is maximized, since Qκ does not depend on frequency (at least for the distances D<<λ of interest for which the quasi-static approximation is still valid). Therefore, the optimal frequency is independent of the distance D between the two rods and lies between the two frequencies where the single-rod Q1 and Q2 peak. Typically, one should tune the inductively-loaded conducting rods, so that their angular eigenfrequencies are close to {tilde over (ω)} within {tilde over (Γ)}, which is half the angular frequency width for which √{square root over (Q1Q2)}/Qκ>{tilde over (()}{tilde over (√)}{tilde over ((√{square root over (Q1Q2)}/Qκ))}/2.
  • Referring to Table 6, in parentheses (for similarity to previous tables) analytical results based on the above are shown for two systems each composed of a matched pair of the loaded rods described in Table 5. The average wavelength and loss rates are shown along with the coupling rate and coupling to loss ratio figure-of-merit κ/Γ as a function of the coupling distance D, for the two cases. Note that for Γrad the single-rod value is used. Again we chose Lc
    Figure US20100253152A1-20101007-P00001
    Ls to make the triangular-current assumption a good one and computed MC numerically from Eq.(6). The results show that for medium distances D/h=10−3 the expected coupling-to-loss ratios are in the range κ/Γ˜0.5-100.
  • TABLE 6
    pair of rods D/h Qκ = ω/2κ κ/Γ
    h = 30 cm, a = 2 cm 3 (70.3) (105.0)
    μ = 1, rBc = 2 cm, aBc = 0.88 mm, 5  (389) (19.0)
    NBc = 129 7 (1115) (6.62)
    λ/h ≈ 404 10 (3321) (2.22)
    Q ≈ 7380
    h = 10 cm, a = 2 mm 3  (120) (32.4)
    μ = 1, rBc = 5 mm, aBc = 0.25 mm, 5  (664) (5.85)
    NBc = 103 7 (1900) (2.05)
    λ/h ≈ 214 10 (5656) (0.69)
    Q ≈ 3886
  • Dielectric Disks
  • In some embodiments, one or more of the resonant objects are dielectric objects, such as disks. Consider a two dimensional dielectric disk object, as shown in FIG. 6, of radius r and relative permittivity s surrounded by air that supports high-Q “whispering-gallery” resonant modes. The loss mechanisms for the energy stored inside such a resonant system are radiation into free space and absorption inside the disk material. High-Qrad and long-tailed subwavelength resonances can be achieved when the dielectric permittivity E is large and the azimuthal field variations are slow (namely of small principal number m). Material absorption is related to the material loss tangent: Qabs˜Re{ε}/Im{ε}. Mode-solving calculations for this type of disk resonances were performed using two independent methods: numerically, 2D finite-difference frequency-domain (FDFD) simulations (which solve Maxwell's Equations in frequency domain exactly apart for spatial discretization) were conducted with a resolution of 30 pts/r; analytically, standard separation of variables (SV) in polar coordinates was used.
  • TABLE 7
    single disk λ/r Qabs Qrad Q
    Re{ε} = 147.7, m = 2 20.01 (20.00) 10103 (10075) 1988 (1992) 1661 (1663)
    Re{ε} = 65.6, m = 3 9.952 (9.950) 10098 (10087) 9078 (9168) 4780 (4802)
  • The results for two TE-polarized dielectric-disk subwavelength modes of λ/r≧10 are presented in Table 7. Table 7 shows numerical FDFD (and in parentheses analytical SV) results for the wavelength and absorption, radiation and total loss rates, for two different cases of subwavelength-disk resonant modes. Note that disk-material loss-tangent Im{ε}/Re{ε}=10−4 was used. (The specific parameters corresponding to the plot in FIG. 6. are highlighted with bold in the table.) The two methods have excellent agreement and imply that for a properly designed resonant low-loss-dielectric object values of Qrad≧2000 and Qabs˜10000 are achievable. Note that for the 3D case the computational complexity would be immensely increased, while the physics would not be significantly different. For example, a spherical object of ε=147.7 has a whispering gallery mode with m=2, Qrad=13962, and λ/r=17.
  • The required values of s, shown in Table 7, might at first seem unrealistically large. However, not only are there in the microwave regime (appropriate for approximately meter-range coupling applications) many materials that have both reasonably high enough dielectric constants and low losses (e.g. Titania, Barium tetratitanate, Lithium tantalite etc.), but also c could signify instead the effective index of other known subwavelength surface-wave systems, such as surface modes on surfaces of metallic materials or plasmonic (metal-like, negative-s) materials or metallo-dielectric photonic crystals or plasmono-dielectric photonic crystals.
  • To calculate now the achievable rate of energy transfer between two disks 1 and 2, as shown in FIG. 7 we place them at distance D between their centers. Numerically, the FDFD mode-solver simulations give κ through the frequency splitting (=2κ) of the normal modes of the combined system, which are even and odd superpositions of the initial single-disk modes; analytically, using the expressions for the separation-of-variables eigenfields E1,2(r) CMT gives κ through κ=ωω/2·∫d32(r)E2*(r)E1(r)/∫d3rε(r)|E1(r)|2 where εj(r) and ε(r) are the dielectric functions that describe only the disk j (minus the constant eo background) and the whole space respectively. Then, for medium distances D/r=10−3 and for non-radiative coupling such that D<2rc, where rc=mλ/2π is the radius of the radiation caustic, the two methods agree very well, and we finally find , as shown in Table 8, coupling-to-loss ratios in the range κ/Γ˜1-50. Thus, for the analyzed embodiments, the achieved figure-of-merit values are large enough to be useful for typical applications, as discussed below.
  • TABLE 8
    two disks D/r Qrad Q = ω/2Γ ω/2κ κ/Γ
    Re{ε} = 147.7, 3 2478 1989 46.9 (47.5) 42.4 (35.0)
    m = 2 λ/r ≈ 20 5 2411 1946 298.0 (298.0) 6.5 (5.6)
    Qabs ≈ 10093 7 2196 1804 769.7 (770.2) 2.3 (2.2)
    10 2017 1681 1714 (1601) 0.98 (1.04)
    Re{ε} = 65.6, 3 7972 4455 144 (140) 30.9 (34.3)
    m = 3 λ/r ≈ 10 5 9240 4824 2242 (2083) 2.2 (2.3)
    Qabs ≈ 10096 7 9187 4810 7485 (7417) 0.64 (0.65)
  • Note that even though particular embodiments are presented and analyzed above as examples of systems that use resonant electromagnetic coupling for wireless energy transfer, those of self-resonant conducting coils, capacitively-loaded resonant conducting coils and resonant dielectric disks, any system that supports an electromagnetic mode with its electromagnetic energy extending much further than its size can be used for transferring energy. For example, there can be many abstract geometries with distributed capacitances and inductances that support the desired kind of resonances. In any one of these geometries, one can choose certain parameters to increase and/or optimize √{square root over (Q1Q2)}/Qκ or, if the Q's are limited by external factors, to increase and/or optimize for Qκ.
  • System Sensitivity to Extraneous Objects
  • In general, the overall performance of particular embodiment of the resonance-based wireless energy-transfer scheme depends strongly on the robustness of the resonant objects' resonances. Therefore, it is desirable to analyze the resonant objects' sensitivity to the near presence of random non-resonant extraneous objects. One appropriate analytical model is that of “perturbation theory” (PT), which suggests that in the presence of an extraneous object e the field amplitude a1(t) inside the resonant object 1 satisfies, to first order:
  • a 1 t = - ( ω 1 - Γ 1 ) a 1 + ( κ 11 - e + Γ 1 - e ) a 1 ( 11 )
  • where again ω1 is the frequency and Γl the intrinsic (absorption, radiation etc.) loss rate, while κ11-e is the frequency shift induced onto 1 due to the presence of e and Γ1-e is the extrinsic due to e (absorption inside e, scattering from e etc.) loss rate. The first-order PT model is valid only for small perturbations. Nevertheless, the parameters κ11-e, r1-e are well defined, even outside that regime, if α1 is taken to be the amplitude of the exact perturbed mode. Note also that interference effects between the radiation field of the initial resonant-object mode and the field scattered off the extraneous object can for strong scattering (e.g. off metallic objects) result in total radiation-Γ1-e's that are smaller than the initial radiation-Γ1 (namely Γ1-e is negative).
  • The frequency shift is a problem that can be “fixed” by applying to one or more resonant objects a feedback mechanism that corrects its frequency. For example, referring to FIG. 8 a, in some embodiments each resonant object is provided with an oscillator at fixed frequency and a monitor which determines the frequency of the object. Both the oscillator and the monitor are coupled to a frequency adjuster which can adjust the frequency of the resonant object by, for example, adjusting the geometric properties of the object (e.g. the height of a self-resonant coil, the capacitor plate spacing of a capacitively-loaded loop or coil, the dimensions of the inductor of an inductively-loaded rod, the shape of a dielectric disc, etc.) or changing the position of a non-resonant object in the vicinity of the resonant object. The frequency adjuster determines the difference between the fixed frequency and the object frequency and acts to bring the object frequency into alignment with the fixed frequency. This technique assures that all resonant objects operate at the same fixed frequency, even in the presence of extraneous objects.
  • As another example, referring to FIG. 8 b, in some embodiments, during energy transfer from a source object to a device object, the device object provides energy to a load, and an efficiency monitor measures the efficiency of the transfer. A frequency adjuster coupled to the load and the efficiency monitor acts to adjust the frequency of the object to maximize the transfer efficiency.
  • In various embodiments, other frequency adjusting schemes may be used which rely on information exchange between the resonant objects. For example, the frequency of a source object can be monitored and transmitted to a device object, which is in turn synched to this frequency using frequency adjusters as described above. In other embodiments the frequency of a single clock may be transmitted to multiple devices, and each device then synched to that frequency.
  • Unlike the frequency shift, the extrinsic loss can be detrimental to the functionality of the energy-transfer scheme, because it is difficult to remedy, so the total loss rate Γ1[e]11-e (and the corresponding figure-of-merit κ[e]/√{square root over (Γ1[e]Γ2[e])}, where κ[e] the perturbed coupling rate) should be quantified.
  • Capacitively-Loaded Conducting Loops or Coils
  • In embodiments using primarily magnetic resonances, the influence of extraneous objects on the resonances is nearly absent. The reason is that, in the quasi-static regime of operation (r
    Figure US20100253152A1-20101007-P00002
    λ) that we are considering, the near field in the air region surrounding the resonator is predominantly magnetic (e.g. for coils with h
    Figure US20100253152A1-20101007-P00004
    2r most of the electric field is localized within the self-capacitance of the coil or the externally loading capacitor), therefore extraneous non-conducting objects e that could interact with this field and act as a perturbation to the resonance are those having significant magnetic properties (magnetic permeability Re{μ}>1 or magnetic loss Im{μ}>0). Since almost all every-day non-conducting materials are non-magnetic but just dielectric, they respond to magnetic fields in the same way as free space, and thus will not disturb the resonance of the resonator. Extraneous conducting materials can however lead to some extrinsic losses due to the eddy currents induced on their surface.
  • As noted above, an extremely important implication of this fact relates to safety considerations for human beings. Humans are also non-magnetic and can sustain strong magnetic fields without undergoing any risk. A typical example, where magnetic fields B˜1T are safely used on humans, is the Magnetic Resonance Imaging (MRI) technique for medical testing. In contrast, the magnetic near-field required in typical embodiments in order to provide a few Watts of power to devices is only B˜10−4 T, which is actually comparable to the magnitude of the Earth's magnetic field. Since, as explained above, a strong electric near-field is also not present and the radiation produced from this non-radiative scheme is minimal, it is reasonable to expect that our proposed energy-transfer method should be safe for living organisms.
  • One can, for example, estimate the degree to which the resonant system of a capacitively-loaded conducting-wire coil has mostly magnetic energy stored in the space surrounding it. If one ignores the fringing electric field from the capacitor, the electric and magnetic energy densities in the space surrounding the coil come just from the electric and magnetic field produced by the current in the wire; note that in the far field, these two energy densities must be equal, as is always the case for radiative fields. By using the results for the fields produced by a subwavelength (r
    Figure US20100253152A1-20101007-P00004
    λ) current loop (magnetic dipole) with h=0, we can calculate the ratio of electric to magnetic energy densities, as a function of distance Dp from the center of the loop (in the limit r
    Figure US20100253152A1-20101007-P00004
    Dp) and the angle θ with respect to the loop axis:
  • u e ( x ) u m ( x ) = ɛ o E ( x ) 2 μ o H ( x ) 2 = ( 1 + 1 x 2 ) sin 2 θ ( 1 x 2 + 1 x 4 ) 4 cos 2 θ + ( 1 - 1 x 2 + 1 x 4 ) sin 2 θ ; x = 2 π D p λ S p u e ( x ) S S p u m ( x ) S = 1 + 1 x 2 1 + 1 x 2 + 3 x 4 ; x = 2 π D p λ , ( 12 )
  • where the second line is the ratio of averages over all angles by integrating the electric and magnetic energy densities over the surface of a sphere of radius Dp. From Eq.(12) it is obvious that indeed for all angles in the near field (x
    Figure US20100253152A1-20101007-P00004
    1) the magnetic energy density is dominant, while in the far field (x
    Figure US20100253152A1-20101007-P00001
    1) they are equal as they should be. Also, the preferred positioning of the loop is such that objects which may interfere with its resonance lie close to its axis (θ=0), where there is no electric field. For example, using the systems described in Table 4, we can estimate from Eq.(12) that for the loop of r=30 cm at a distance Dp=10r=3 m the ratio of average electric to average magnetic energy density would be ˜12% and at Dp=3r=90 cm it would be ˜1%, and for the loop of r=10 cm at a distance Dp=10r=1 m the ratio would be ˜33% and at Dp=3r=30 cm it would be ˜2.5%. At closer distances this ratio is even smaller and thus the energy is predominantly magnetic in the near field, while in the radiative far field, where they are necessarily of the same order (ratio→1), both are very small, because the fields have significantly decayed, as capacitively-loaded coil systems are designed to radiate very little. Therefore, this is the criterion that qualifies this class of resonant system as a magnetic resonant system.
  • To provide an estimate of the effect of extraneous objects on the resonance of a capacitively-loaded loop including the capacitor fringing electric field, we use the perturbation theory formula, stated earlier, Γ1−e abs1/4·∫d3rIm{εe(r)}|E1(r)|2/U with the computational FEFD results for the field of an example like the one shown in the plot of FIG. 5 and with a rectangular object of dimensions 30 cm×30 cm×1.5 m and permittivity ε=49+16i (consistent with human muscles) residing between the loops and almost standing on top of one capacitor (˜3 cm away from it) and find Qc−h abs˜105 and for ˜10 cm away Qc−h abs˜5·105. Thus, for ordinary distances (˜1 m) and placements (not immediately on top of the capacitor) or for most ordinary extraneous objects e of much smaller loss-tangent, we conclude that it is indeed fair to say that Wc−c abs→∞. The only perturbation that is expected to affect these resonances is a close proximity of large metallic structures.
  • Self-resonant coils are more sensitive than capacitively-loaded coils, since for the former the electric field extends over a much larger region in space (the entire coil) rather than for the latter (just inside the capacitor). On the other hand, self-resonant coils are simple to make and can withstand much larger voltages than most lumped capacitors.
  • In general, different embodiments of resonant systems have different degree of sensitivity to external perturbations, and the resonant system of choice depends on the particular application at hand, and how important matters of sensitivity or safety are for that application. For example, for a medical implantable device (such as a wirelessly powered artificial heart) the electric field extent must be minimized to the highest degree possible to protect the tissue surrounding the device. In such cases where sensitivity to external objects or safety is important, one should design the resonant systems so that the ratio of electric to magnetic energy density ue/um is reduced or minimized at most of the desired (according to the application) points in the surrounding space.
  • Dielectric Disks
  • In embodiments using resonances that are not primarily magnetic, the influence of extraneous objects may be of concern. For example, for dielectric disks, small, low-index, low-material-loss or far-away stray objects will induce small scattering and absorption. In such cases of small perturbations these extrinsic loss mechanisms can be quantified using respectively the analytical first-order perturbation theory formulas All perturbations

  • Γ1−e rad1 ∫d 3 rRe{ε e(r)}|E 1(r)|2 /U

  • and

  • Γ1−c abs1/4·∫d 3 rIm{ε e(r)}|E 1(r)|2 /U
  • where U=½∫d3rε (r)|E1(r)|2 is the total resonant electromagnetic energy of the unperturbed mode. As one can see, both of these losses depend on the square of the resonant electric field tails E1 at the site of the extraneous object. In contrast, the coupling rate from object 1 to another resonant object 2 is, as stated earlier,

  • κ=ω1/2·∫d 3 2(r)E 2*(r)E 1(r)/∫d 3 rε(r)|E 1(r)|2
  • and depends linearly on the field tails E1 of 1 inside 2. This difference in scaling gives us confidence that, for, for example, exponentially small field tails, coupling to other resonant objects should be much faster than all extrinsic loss rates (κ
    Figure US20100253152A1-20101007-P00001
    Γ1−e), at least for small perturbations, and thus the energy-transfer scheme is expected to be sturdy for this class of resonant dielectric disks. However, we also want to examine certain possible situations where extraneous objects cause perturbations too strong to analyze using the above first-order perturbation theory approach. For example, we place a dielectric disk c close to another off-resonance object of large Re{ε}, Im{ε} and of same size but different shape (such as a human being h), as shown in FIG. 9 a, and a roughened surface of large extent but of small Re{ε}, Im{ε} (such as a wall w), as shown in FIG. 9 b. For distances Dh/w/r=10−3 between the disk-center and the “human”-center or “wall”, the numerical FDFD simulation results presented in FIGS. 9 a and 9 b suggest that, the disk resonance seems to be fairly robust, since it is not detrimentally disturbed by the presence of extraneous objects, with the exception of the very close proximity of high-loss objects. To examine the influence of large perturbations on an entire energy-transfer system we consider two resonant disks in the close presence of both a “human” and a “wall”. Comparing FIG. 7 to FIG. 9 c, the numerical FDFD simulations show that the system performance deteriorates from κ/Γc˜1-50 to κ[hw]/Γc[hw]˜0.5-10 i.e. only by acceptably small amounts.
  • Inductively-loaded conducting rods may also be more sensitive than capacitively-loaded coils, since they rely on the electric field to achieve the coupling.
  • System Efficiency
  • In general, another important factor for any energy transfer scheme is the transfer efficiency. Consider again the combined system of a resonant source s and device d in the presence of a set of extraneous objects e. The efficiency of this resonance-based energy-transfer scheme may be determined, when energy is being drained from the device at rate Γwork for use into operational work. The coupled-mode-theory equation for the device field-amplitude is
  • a d t = - ( ω - Γ d [ e ] ) a d + κ [ e ] a s - Γ work a d , ( 13 )
  • where Γd[e]d[e] radd[e] absd[e] rad+(Γd absd−e abs) is the net perturbed-device loss rate, and similarly we define Γs[c] for the perturbed-source. Different temporal schemes can be used to extract power from the device (e.g. steady-state continuous-wave drainage, instantaneous drainage at periodic times and so on) and their efficiencies exhibit different dependence on the combined system parameters. For simplicity, we assume steady state, such that the field amplitude inside the source is maintained constant, namely αs(t)=Ase−iωt, so then the field amplitude inside the device is αd(t)=Ade−iωt with Ad/As=iκ[e]/(Γd[e]work). The various time-averaged powers of interest are then: the useful extracted power is Pwork=2Γwork|Ad|2, the radiated (including scattered) power is Prad=2Γs[e] rad|As|2+2Γd[e] rad|Ad|2, the power absorbed at the source/device is Ps/d=2Γs/d abs|As/d|2, and at the extraneous objects Pe=2Γs−e abs|As|2+2Γd−e abs|Ad|2. From energy conservation, the total time-averaged power entering the system is Ptotal=Pwork+Prad+Ps+Pd+Pc. Note that the reactive powers, which are usually present in a system and circulate stored energy around it, cancel at resonance (which can be proven for example in electromagnetism from Poynting's Theorem) and do not influence the power-balance calculations. The working efficiency is then:
  • η work P work P total = 1 1 + Γ d [ e ] Γ work · [ 1 + 1 fom [ e ] 2 ( 1 + Γ work Γ d [ c ] ) 2 ] , ( 14 )
  • where fom[c][e]/√{square root over (Γs[e]Γd[e] )}is the distance-dependent figure-of-merit of the perturbed resonant energy-exchange system. To derive Eq.(14), we have assumed that the rate Γsupply, at which the power supply is feeding energy to the resonant source, is Γsupplys[e]2/(Γd[e]work), such that there are zero reflections of the fed power Ptotal back into the power supply.
  • Example Capacitively-Loaded Conducting Loops
  • Referring to FIG. 10, to rederive and express this formula (14) in terms of the parameters which are more directly accessible from particular resonant objects, e.g. the capacitively-loaded conducting loops, one can consider the following circuit-model of the system, where the inductances Ls, Ld represent the source and device loops respectively, Rs, Rd their respective losses, and Cs, Cd are the required corresponding capacitances to achieve for both resonance at frequency ω. A voltage generator Vg is considered to be connected to the source and a work (load) resistance Rw to the device. The mutual inductance is denoted by M.
  • Then from the source circuit at resonance (ωLs=1/ωCs):
  • V g = I s R s - MI d 1 2 V g * I s = 1 2 I s 2 R s + 1 2 MI d * I s ,
  • and from the device circuit at resonance (ωLd=1/ωCd):

  • 0=I d(R d +R w)−jωMI s
    Figure US20100253152A1-20101007-P00006
    jωMI s =I d(R d +R w)
  • So by substituting the second to the first:
  • 1 2 V g * I s = 1 2 I s 2 R s + 1 2 I d 2 ( R d + R w ) .
  • Now we take the real part (time-averaged powers) to find the efficiency:
  • P g Re { 1 2 V g * I s } = P s + P d + P w η work P w P tot = R w I s I d 2 · R s + R d + R w . Namely , η work = R w ( R d + R w ) 2   (   ω M ) 2 · R s + R d + R w ,
  • which with Γwork=Rw/2Ld, Γd=Rd/2Ld, Γs=Rs/2Ls, and κ=ωM/2√{square root over (LsLd)}, becomes the general Eq.(14). [End of Example]
  • From Eq.(14) one can find that the efficiency is optimized in terms of the chosen work-drainage rate, when this is chosen to be Γworkd[e]=rsupply/rs[e]=√{square root over (1+fom[e] 2)}>1. Then, ηwork is a function of the fom[e] parameter only as shown in FIG. 11 with a solid black line. One can see that the efficiency of the system is η>17% for fom[e]>1, large enough for practical applications. Thus, the efficiency can be further increased towards 100% by optimizing fom[c] as described above. The ratio of conversion into radiation loss depends also on the other system parameters, and is plotted in FIG. 5 for the conducting loops with values for their parameters within the ranges determined earlier.
  • For example, consider the capacitively-loaded coil embodiments described in Table 4, with coupling distance D/r=7, a “human” extraneous object at distance Dh from the source, and that Pwork=10 W must be delivered to the load. Then, we have (based on FIG. 11) Q[s] rad=Qd[h] rad˜104, Qs abs−Qd abs˜103, Qκ˜500, and Qd−h abs→∞, Qs−h abs˜105 at Dh˜3 cm and Qs−h˜5·105 at Dh˜10 cm. Therefore fom[h]˜2, so we find η≈38%, Prad≈1.5 W, Ps≈11 W, Pd≈4 W, and most importantly ηh≈0.4%, Ph=0.1 W at Dh˜3 cm and ηh≈0.1%, Ph=0.02 W at Dh˜10 cm.
  • Overall System Performance
  • In many cases, the dimensions of the resonant objects will be set by the particular application at hand. For example, when this application is powering a laptop or a cell-phone, the device resonant object cannot have dimensions larger that those of the laptop or cell-phone respectively. In particular, for a system of two loops of specified dimensions, in terms of loop radii rs,d and wire radii as,d, the independent parameters left to adjust for the system optimization are: the number of turns Ns,d, the frequency f, the work-extraction rate (load resistance) Γwork and the power-supply feeding rate Γsupply.
  • In general, in various embodiments, the primary dependent variable that one wants to increase or optimize is the overall efficiency η. However, other important variables need to be taken into consideration upon system design. For example, in embodiments featuring capacitively-loaded coils, the design may be constrained by, for example, the currents flowing inside the wires Is,d and the voltages across the capacitors Vs,d. These limitations can be important because for ˜Watt power applications the values for these parameters can be too large for the wires or the capacitors respectively to handle. Furthermore, the total loaded Qtot=ωLd/(Rd+Rw) of the device is a quantity that should be preferably small, because to match the source and device resonant frequencies to within their Q's, when those are very large, can be challenging experimentally and more sensitive to slight variations. Lastly, the radiated powers Prod,s,d should be minimized for safety concerns, even though, in general, for a magnetic, non-radiative scheme they are already typically small.
  • In the following, we examine then the effects of each one of the independent variables on the dependent ones. We define a new variable wp to express the work-drainage rate for some particular value of fom[c] through Γworkd[c]=√{square root over (1+wp·fom[e] 2)}. Then, in some embodiments, values which impact the choice of this rate are: Γworkd[e]=1
    Figure US20100253152A1-20101007-P00005
    wp=0 to minimize the required energy stored in the source (and therefore Is and Vs), Γworkd[e]=√{square root over (1+fom[c] 2)}>1
    Figure US20100253152A1-20101007-P00005
    wp=1 to increase the efficiency, as seen earlier, or Γworkd[e]
    Figure US20100253152A1-20101007-P00001
    1
    Figure US20100253152A1-20101007-P00005
    wp
    Figure US20100253152A1-20101007-P00001
    1 to decrease the required energy stored in the device (and therefore Id and Vd) and to decrease or minimize Qtot=ωLd/(Rd+Rw)=ω/[2(Γdwork)]. Similar is the impact choice of the power supply feeding rate Γsupply, with the roles of the source and the device reversed.
  • Increasing Ns and Nd increases κ/√{square root over (ΓsΓd )}and thus efficiency significantly, as seen before, and also decreases the currents Is and Id, because the inductance of the loops increases, and thus the energy
  • U s , d = 1 2 L s , d I s , d 2
  • required for given output power Pwork can be achieved with smaller currents. However, increasing Nd increases Qtot, Prad,d and the voltage across the device capacitance Vd, which unfortunately ends up being, in typical embodiments one of the greatest limiting factors of the system. To explain this, note that it is the electric field that really induces breakdown of the capacitor material (e.g. 3 kV/mm for air) and not the voltage, and that for the desired (close to the optimal) operational frequency, the increased inductance Ld implies reduced required capacitance Cd, which could be achieved in principle, for a capacitively-loaded device coil by increasing the spacing of the device capacitor plates dd and for a self-resonant coil by increasing through hd the spacing of adjacent turns, resulting in an electric field (≈Vd/dd for the former case) that actually decreases with Nd; however, one cannot in reality increase dd or hd too much, because then the undesired capacitance fringing electric fields would become very large and/or the size of the coil might become too large; and, in any case, for certain applications extremely high voltages are not desired. A similar increasing behavior is observed for the source Prod,s and Vs upon increasing Ns. As a conclusion, the number of turns Nc and Nd have to be chosen the largest possible (for efficiency) that allow for reasonable voltages, fringing electric fields and physical sizes.
  • With respect to frequency, again, there is an optimal one for efficiency, and Qtot is approximately maximum, close to that optimal frequency. For lower frequencies the currents get worse (larger) but the voltages and radiated powers get better (smaller). Usually, one should pick either the optimal frequency or somewhat lower.
  • One way to decide on an operating regime for the system is based on a graphical method. In FIG. 12, for two loops of rs=25 cm, rd=15 cm, hs=hd=0, as=ad=3 mm and distance D=2 mm between them we plot all the above dependent variables (currents, voltages and radiated powers normalized to 1 Watt of output power) in terms of frequency and Nd, given some choice for wp and Ns. The Figure depicts all of the dependencies explained above. We can also make a contour plot of the dependent variables as functions of both frequency and wp but for both Ns and Nd fixed. The results are shown in FIG. 13 for the same loop dimensions and distance. For example, a reasonable choice of parameters for the system of two loops with the'dimensions given above are: Ns=2, Nd=6, f=10 MHz and wp=10, which gives the following performance characteristics: ηwork=20.6%, Qtot=1264, Is=7.2 A, Id=1.4 A, Vs=2.55 kV, Vd=2.30 kV, Prad,s=0.15 W, Prad,d=0.006 W Note that the results in FIGS. 12 and 13, and the just above calculated performance characteristics are made using the analytical formulas provided above, so they are expected to be less accurate for large values of Ns, Nd, still they give a good estimate of the scalings and the orders of magnitude.
  • Finally, one could additionally optimize for the source dimensions, since usually only the device dimensions are limited, as discussed earlier. Namely, one can add rs and as in the set of independent variables and optimize with respect to these too for all the dependent variables of the problem (we saw how to do this only for efficiency earlier). Such an optimization would lead to improved results.
  • Experimental Results
  • An experimental realization of an embodiment of the above described scheme for wireless energy transfer consists of two self-resonant coils of the type described above, one of which (the source coil) is coupled inductively to an oscillating circuit, and the second (the device coil) is coupled inductively to a resistive load, as shown schematically in FIG. 14. Referring to FIG. 14, A is a single copper loop of radius 25 cm that is part of the driving circuit, which outputs a sine wave with frequency 9.9 MHz. s and d are respectively the source and device coils referred to in the text. B is a loop of wire attached to the load (“light-bulb”). The various κ′s represent direct couplings between the objects. The angle between coil d and the loop A is adjusted so that their direct coupling is zero, while coils s and d are aligned coaxially. The direct coupling between B and A and between B and s is negligible.
  • The parameters for the two identical helical coils built for the experimental validation of the power transfer scheme were h=20 cm, a=3 mm, r=30 cm, N=5.25. Both coils are made of copper. Due to imperfections in the construction, the spacing between loops of the helix is not uniform, and we have encapsulated the uncertainty about their uniformity by attributing a 10% (2 cm) uncertainty to h. The expected resonant frequency given these dimensions is f0=10.56±0.3 MHz, which is about 5% off from the measured resonance at around 9.90 MHz.
  • The theoretical Q for the loops is estimated to be ˜2500 (assuming perfect copper of resistivity ρ=1/σ=1.7×10−8 Ωm) but the measured value is 950±50. We believe the discrepancy is mostly due to the effect of the layer of poorly conducting copper oxide on the surface of the copper wire, to which the current is confined by the short skin depth (˜20 μm) at this frequency. We have therefore used the experimentally observed Q (and Γ12=Γ=ω/(2Q) derived from it) in all subsequent computations.
  • The coupling coefficient κ can be found experimentally by placing the two self-resonant coils (fine-tuned, by slightly adjusting h, to the same resonant frequency when isolated) a distance D apart and measuring the splitting in the frequencies of the two resonant modes in the transmission spectrum. According to coupled-mode theory, the splitting in the transmission spectrum should be Δω=2√{square root over (κ2−Γ2)}. The comparison between experimental and theoretical results as a function of distance when the two the coils are aligned coaxially is shown in FIG. 15.
  • FIG. 16 shows a comparison of experimental and theoretical values for the parameter κ/Γ as a function of the separation between the two coils. The theory values are obtained by using the theoretically obtained κ and the experimentally measured Γ. The shaded area represents the spread in the theoretical κ/Γ due to the ˜5% uncertainty in Q.
  • As noted above, the maximum theoretical efficiency depends only on the parameter κ/√{square root over (Γ1Γ2)}=κ/Γ, plotted as a function of distance in FIG. 17. The coupling to loss ratio κ/Γ is greater than 1 even for D=2.4 m (eight times the radius of the coils), thus the system is in the strongly-coupled regime throughout the entire range of distances probed.
  • The power supply circuit was a standard Colpitts oscillator coupled inductively to the source coil by means of a single loop of copper wire 25 cm in radius (see FIG. 14). The load consisted of a previously calibrated light-bulb, and was attached to its own loop of insulated wire, which was in turn placed in proximity of the device coil and inductively coupled to it. Thus, by varying the distance between the light-bulb and the device coil, the parameter Γwork/Γ was adjusted so that it matched its optimal value, given theoretically by √{square root over (1+κ2/(Γ1Γ2))}. Because of its inductive nature, the loop connected to the light-bulb added a small reactive component to Γwork which was compensated for by slightly returning the coil. The work extracted was determined by adjusting the power going into the Colpitts oscillator until the light-bulb at the load was at its full nominal brightness.
  • In order to isolate the efficiency of the transfer taking place specifically between the source coil and the load, we measured the current at the mid-point of each of the self-resonant coils with a current-probe (which was not found to lower the Q of the coils noticeably.) This gave a measurement of the current parameters I1 and I2 defined above. The power dissipated in each coil was then computed from P1,2=ΓL|/I1,2|2, and the efficiency was directly obtained from η=Pwork/(P1+P2+Pwork). To ensure that the experimental setup was well described by a two-object coupled-mode theory model, we positioned the device coil such that its direct coupling to the copper loop attached to the Colpitts oscillator was zero. The experimental results are shown in FIG. 17, along with the theoretical prediction for maximum efficiency, given by Eq.(14).
  • Using this embodiment, we were able to transfer significant amounts of power using this setup, fully lighting up a 60 W light-bulb from distances more than 2 m away, for example. As an additional test, we also measured the total power going into the driving circuit. The efficiency of the wireless transfer itself was hard to estimate in this way, however, as the efficiency of the Colpitts oscillator itself is not precisely known, although it is expected to be far from 100%. Nevertheless, this gave an overly conservative lower bound on the efficiency. When transferring 60 W to the load over a distance of 2 m, for example, the power flowing into the driving circuit was 400 W. This yields an overall wall-to-load efficiency of ˜15%, which is reasonable given the expected ˜40% efficiency for the wireless power transfer at that distance and the low efficiency of the driving circuit.
  • From the theoretical treatment above, we see that in typical embodiments it is important that the coils be on resonance for the power transfer to be practical. We found experimentally that the power transmitted to the load dropped sharply as one of the coils was detuned from resonance. For a fractional detuning Δf/f0 of a few times the inverse loaded Q, the induced current in the device coil was indistinguishable from noise.
  • The power transfer was not found to be visibly affected as humans and various everyday objects, such as metallic and wooden furniture, as well as electronic devices large and small, were placed between the two coils, even when they drastically obstructed the line of sight between source and device. External objects were found to have an effect only when they were closer than 10 cm from either one of the coils. While some materials (such as aluminum foil, styrofoam and humans) mostly just shifted the resonant frequency, which could in principle be easily corrected with a feedback circuit of the type described earlier, others (cardboard, wood, and PVC) lowered Q when placed closer than a few centimeters from the coil, thereby lowering the efficiency of the transfer.
  • We believe that this method of power transfer should be safe for humans. When transferring 60 W (more than enough to power a laptop computer) across 2 m, we estimated that the magnitude of the magnetic field generated is much weaker than the Earth's magnetic field for all distances except for less than about 1 cm away from the wires in the coil, an indication of the safety of the scheme even after long-term use. The power radiated for these parameters was ˜5 W, which is roughly an order of magnitude higher than cell phones but could be drastically reduced, as discussed below.
  • Although the two coils are currently of identical dimensions, it is possible to make the device coil small enough to fit into portable devices without decreasing the efficiency. One could, for instance, maintain the product of the characteristic sizes of the source and device coils constant.
  • These experiments demonstrated experimentally a system for power transfer over medium range distances, and found that the experimental results match theory well in multiple independent and mutually consistent tests.
  • We believe that the efficiency of the scheme and the distances covered could be appreciably improved by silver-plating the coils, which should increase their Q, or by working with more elaborate geometries for the resonant objects. Nevertheless, the performance characteristics of the system presented here are already at levels where they could be useful in practical applications.
  • Applications
  • In conclusion, we have described several embodiments of a resonance-based scheme for wireless non-radiative energy transfer. Although our consideration has been for a static geometry (namely κ and Γe were independent of time), all the results can be applied directlyfor the dynamic geometries of mobile objects, since the energy-transfer time κ−1 (˜1 μs-1 ms for microwave applications) is much shorter than any timescale associated with motions of macroscopic objects. Analyses of very simple implementation geometries provide encouraging performance characteristics and further improvement is expected with serious design optimization. Thus the proposed mechanism is promising for many modern applications.
  • For example, in the macroscopic world, this scheme could potentially be used to deliver power to for example, robots and/or computers in a factory room, or electric buses on a highway. In some embodiments source-object could be an elongated “pipe” running above the highway, or along the ceiling.
  • Some embodiments of the wireless transfer scheme can provide energy to power or charge devices that are difficult or impossible to reach using wires or other techniques. For example some embodiments may provide power to implanted medical devices (e.g. artificial hearts, pacemakers, medicine delivery pumps, etc.) or buried underground sensors.
  • In the microscopic world, where much smaller wavelengths would be used and smaller powers are needed, one could use it to implement optical inter-connects for CMOS electronics, or to transfer energy to autonomous nano-objects (e.g. MEMS or nano-robots) without worrying much about the relative alignment between the sources and the devices. Furthermore, the range of applicability could be extended to acoustic systems, where the source and device are connected via a common condensed-matter object.
  • In some embodiments, the techniques described above can provide non-radiative wireless transfer of information using the localized near fields of resonant object. Such schemes provide increased security because no information is radiated into the far-field, and are well suited for mid-range communication of highly sensitive information.
  • A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention.

Claims (57)

  1. 1. A wireless power transmitter system for transmitting power to at least one high-Q resonator, comprising:
    a connection to a source of line power;
    a modulating part, which converts said line power to create a first frequency of lower than 1 MHz; and
    a transmitter part, including a transmitting high-Q resonator formed of a conductive loop with a capacitor that brings said high-Q resonator to resonance at said first frequency, and which produces a magnetic field based on said source of line power, said transmitter part having a Q factor at said frequency, where said Q factor is at least 300.
  2. 2. A system as in claim 1, wherein said Q factor is at least 1000.
  3. 3. A system as in claim 1, wherein said transmitting high-Q resonator uses stranded wire for said conductive loop formed of multiple strands which each carry current but are insulated from one another.
  4. 4. A system as in claim 1, wherein said transmitting high-Q resonator uses material inside said conductive loop.
  5. 5. A system as in claim 4, wherein said material is formed of a magnetic material.
  6. 6. A system as in claim 5, wherein said conductive loop is formed of a stranded wire material formed of multiple strands which each carry current but are insulated from each other.
  7. 7. A system as in claim 6, wherein said stranded wire material is Litz wire.
  8. 8. A system as in claim 1, further comprising at least one resonator, tuned to repeat a magnetic field produced by said transmitter.
  9. 9. A system as in claim 1, wherein said first frequency is lower than 500 kHz.
  10. 10. A system as in claim 1, further comprising a receiver that has a high-Q resonator formed of a coil loop and a capacitor which makes a resonant circuit at said first frequency that has magnetic energy induced therein by said transmitter, and which produces output power.
  11. 11. A system as in claim 10, wherein said high-Q resonator in said receiver uses stranded wire in said coil loop formed of multiple strands which each carry current but are each insulated from one another.
  12. 12. A system as in claim 10, wherein said high-Q resonator in said receiver uses magnetic material in said coil loop.
  13. 13. A wireless power receiver system for receiving power from at least one high-Q resonator, comprising:
    a receiver part, including a receiving high-Q resonator formed of a conductive loop with a capacitor that brings said high-Q resonator to resonance at a first frequency, and which receives a magnetic field and produces an output that is based on the magnetic field, said first frequency being lower than 1 MHz; and
    a circuit, which couples to said output to produce a power output.
  14. 14. A system as in claim 13, wherein a Q factor of said receiver part is at least 300.
  15. 15. A system as in claim 13, wherein said receiving high-Q resonator uses stranded wire for said conductive loop formed of multiple strands which each carry current but are insulated from one another.
  16. 16. A system as in claim 13, wherein said receiving high-Q resonator uses material inside said conductive loop.
  17. 17. A system as in claim 16, wherein said material is formed of a magnetic material.
  18. 18. A system as in claim 17, wherein said conductive loop is formed of a stranded wire material formed of multiple strands which each carry current but are insulated from each other.
  19. 19. A system as in claim 18, wherein said stranded wire material is Litz wire.
  20. 20. A system as in claim 13, further comprising at least one resonator, tuned to repeat a magnetic field at said first frequency.
  21. 21. A system as in claim 13, wherein said first frequency is lower than 500 kHz.
  22. 22. A system as in claim 13, further comprising a transmitter that has a high-Q resonator formed of a coil loop and a capacitor which makes a resonant circuit at said first frequency that has magnetic energy produced therein by a source of line power.
  23. 23. A system as in claim 22, wherein said high-Q resonator in said receiver uses stranded wire in said coil loop.
  24. 24. A system as in claim 10, wherein said high-Q resonator in said receiver uses magnetic material in said coil loop.
  25. 25. A method of transmitting power to at least one high-Q resonator, comprising:
    using electrical power to create a signal having a first frequency of lower than 1 MHz; using a high-Q resonator which is self-resonant at said first frequency to transmit said signal; and using a second resonator a-that is activated by the transmitter to repeat said signal at said first frequency.
  26. 26. A method as in claim 25, wherein said high-Q resonator includes an inductive loop, and a capacitor that brings the high-Q resonator to resonance at said first frequency.
  27. 27. A method as in claim 26, wherein said high-Q resonator is formed of stranded wire formed of multiple strands which each carry current but are each insulated from one another.
  28. 28. A method as in claim 26, wherein said inductive loop includes a magnetic material.
  29. 29. A method as in claim 25, wherein said second resonator is formed of stranded wire.
  30. 30. A method as in claim 25, wherein said second resonator includes a magnetic material.
  31. 31. A wireless power transmitter system for transmitting power to at least one high-Q resonator, comprising:
    a connection to a source of line power;
    a modulating part, which converts said line power to create a first frequency;
    a transmitter part, including a transmitting high-Q resonator formed of a conductive loop with a capacitor that brings said high-Q resonator to resonance at said first frequency, and which produces a magnetic field based on said source of line power, said transmitter part having a Q factor at said frequency; and
    at least a second resonator having no source of power connected to said second resonator, tuned to repeat a magnetic field produced by said transmitter.
  32. 32. A system as in claim 31, wherein said Q factor is at least 1000.
  33. 33. A system as in claim 31, wherein said transmitting high-Q resonator uses stranded wire for said conductive loop formed of multiple strands which each carry current but are each insulated from one another.
  34. 34. A system as in claim 31, wherein said transmitting high-Q resonator uses a magnetic material inside said conductive loop.
  35. 35. A system as in claim 31, wherein said first frequency is lower than 1 MHz.
  36. 36. A system as in claim 31, further comprising a receiver that has a high-Q resonator formed of a coil loop and a capacitor which makes a resonant circuit at said first frequency, where said high-Q resonator has magnetic energy induced therein by said transmitter, and where said receiver produces output power.
  37. 37. A system as in claim 36, wherein said high-Q resonator in said receiver uses stranded wire in said coil loop formed of multiple strands which each carry current but are each insulated from one another.
  38. 38. A system as in claim 36, wherein said high-Q resonator in said receiver uses magnetic material in said coil loop.
  39. 39. A wireless power receiver system for receiving power from at least one high-Q resonator, comprising:
    a receiver part, including a receiving high-Q resonator formed of a conductive loop with a capacitor that brings said high-Q resonator to resonance at a first frequency, and which receives a magnetic field,
    at least one additional resonator having no source of power connected to said additional resonator, tuned to repeat a magnetic field received by a transmitter; and
    a power output, which outputs power received by said receiver part.
  40. 40. A system as in claim 39, wherein said receiving high-Q resonator uses stranded wire for said conductive loop formed of multiple strands which each carry current but are each insulated from one another.
  41. 41. A system as in claim 39, wherein said receiving high-Q resonator uses a magnetic material inside said conductive loop.
  42. 42. A system as in claim 39, wherein said first frequency is lower than 1 MHz.
  43. 43. A wireless power transmitter system for transmitting power to at least one high-Q resonator, comprising:
    a connection to a source of line power;
    a modulating part, which converts said line power to create a first frequency of lower than 1 MHz; and
    a transmitter part, including a transmitting high-Q resonator formed of a conductive loop wound around a magnetic material, with a capacitor that brings said high-Q resonator to resonance at said first frequency, and which produces a magnetic field based on said source of line power.
  44. 44. A system as in claim 43, wherein said transmitting high-Q resonator has a Q factor which is at least 300.
  45. 45. A system as in claim 43, wherein said transmitting high-Q resonator uses stranded wire for said conductive loop formed of multiple strands which each carry current but are each insulated from one another.
  46. 46. A system as in claim 6, wherein said stranded wire material is Litz wire.
  47. 47. A system as in claim 1, further comprising at least one resonator, tuned to repeat a magnetic field produced by said transmitter.
  48. 48. A wireless power receiver system for receiving power from at least one high-Q resonator, comprising:
    a receiver part, including a receiving high-Q resonator formed of a conductive loop wound around magnetic material, with a capacitor that brings said high-Q resonator to resonance at a first frequency, and which receives a magnetic field,
    a power circuit which converts said magnetic field into electrical power, and which outputs power received by said receiver part.
  49. 49. A system as in claim 48, wherein said receiving high-Q resonator uses stranded wire for said conductive loop formed of multiple strands which each carry current but are each insulated from one another.
  50. 50. A system as in claim 48, wherein said first frequency is lower than 1 MHz.
  51. 51. A system as in claim 48, wherein said first frequency is lower than 500 kHz.
  52. 52. A method of transmitting power to at least one high-Q resonator, comprising:
    using electrical power to create a signal having a first frequency;
    using a high-Q resonator which is resonant at said first frequency to transmit said signal; and
    using an additional resonator that is activated by the transmitter to repeat said signal at said first frequency.
  53. 53. A method as in claim 52, wherein said high-Q resonator which is resonant at a first frequency includes an inductive loop, and a capacitor that brings the high-Q resonator to resonance at said first frequency.
  54. 54. A method as in claim 53, wherein said high-Q resonator is formed of stranded wire formed of multiple strands which each carry current but are each insulated from one another.
  55. 55. A method as in claim 53, wherein said inductive loop includes a magnetic material.
  56. 56. A method as in claim 52, wherein said additional resonator is formed of stranded wire.
  57. 57. A method as in claim 52, wherein said additional resonator includes a magnetic material.
US12717559 2005-07-12 2010-03-04 Long range low frequency resonator Abandoned US20100253152A1 (en)

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US69844205 true 2005-07-12 2005-07-12
US11481077 US7741734B2 (en) 2005-07-12 2006-07-05 Wireless non-radiative energy transfer
US90838307 true 2007-03-27 2007-03-27
US90866607 true 2007-03-28 2007-03-28
PCT/US2007/070892 WO2008118178A8 (en) 2007-03-27 2007-06-11 Wireless energy transfer
US12055963 US7825543B2 (en) 2005-07-12 2008-03-26 Wireless energy transfer
US12688339 US20100117456A1 (en) 2005-07-12 2010-01-15 Applications of wireless energy transfer using coupled antennas
US12717559 US20100253152A1 (en) 2005-07-12 2010-03-04 Long range low frequency resonator

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US12717559 Abandoned US20100253152A1 (en) 2005-07-12 2010-03-04 Long range low frequency resonator
US12726742 Abandoned US20100171370A1 (en) 2005-07-12 2010-03-18 Maximizing power yield from wireless power magnetic resonators
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US12726953 Abandoned US20100181844A1 (en) 2005-07-12 2010-03-18 High efficiency and power transfer in wireless power magnetic resonators
US12732399 Abandoned US20100237708A1 (en) 2005-07-12 2010-03-26 Transmitters and receivers for wireless energy transfer
US12766232 Abandoned US20100201205A1 (en) 2005-07-12 2010-04-23 Biological effects of magnetic power transfer
US12784615 Abandoned US20100225175A1 (en) 2005-07-12 2010-05-21 Wireless power bridge
US12787765 Abandoned US20100231053A1 (en) 2005-07-12 2010-05-26 Wireless power range increase using parasitic resonators
US12837675 Abandoned US20100277005A1 (en) 2005-07-12 2010-07-16 Wireless powering and charging station
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US12896328 Abandoned US20110018361A1 (en) 2005-07-12 2010-10-01 Tuning and gain control in electro-magnetic power systems
US12896400 Abandoned US20110025131A1 (en) 2005-07-12 2010-10-01 Packaging and details of a wireless power device
US12939400 Abandoned US20110049998A1 (en) 2005-07-12 2010-11-04 Wireless delivery of power to a fixed-geometry power part
US12949504 Abandoned US20110074218A1 (en) 2005-07-12 2010-11-18 Wireless energy transfer
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US13030395 Abandoned US20110140544A1 (en) 2005-07-12 2011-02-18 Adaptive wireless power transfer apparatus and method thereof
US13030400 Abandoned US20110148219A1 (en) 2005-07-12 2011-02-18 Short range efficient wireless power transfer
US13036177 Abandoned US20110193419A1 (en) 2005-07-12 2011-02-28 Wireless energy transfer
US13040810 Abandoned US20110198939A1 (en) 2005-07-12 2011-03-04 Flat, asymmetric, and e-field confined wireless power transfer apparatus and method thereof
US13051098 Abandoned US20110169339A1 (en) 2005-07-12 2011-03-18 Method and apparatus of load detection for a planar wireless power system
US13051153 Abandoned US20110162895A1 (en) 2005-07-12 2011-03-18 Noncontact electric power receiving device, noncontact electric power transmitting device, noncontact electric power feeding system, and electrically powered vehicle
US13078511 Abandoned US20110181122A1 (en) 2005-07-12 2011-04-01 Wirelessly powered speaker
US13102498 Abandoned US20120248884A1 (en) 2005-07-12 2011-05-06 Wireless power transmission apparatus
US13107293 Abandoned US20110227528A1 (en) 2005-07-12 2011-05-13 Adaptive matching, tuning, and power transfer of wireless power
US13112476 Abandoned US20110221278A1 (en) 2005-07-12 2011-05-20 Power supply system and method of controlling power supply system
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US12726953 Abandoned US20100181844A1 (en) 2005-07-12 2010-03-18 High efficiency and power transfer in wireless power magnetic resonators
US12732399 Abandoned US20100237708A1 (en) 2005-07-12 2010-03-26 Transmitters and receivers for wireless energy transfer
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US12837675 Abandoned US20100277005A1 (en) 2005-07-12 2010-07-16 Wireless powering and charging station
US12862907 Abandoned US20110049996A1 (en) 2005-07-12 2010-08-25 Wireless desktop it environment
US12868852 Abandoned US20100327660A1 (en) 2005-07-12 2010-08-26 Resonators and their coupling characteristics for wireless power transfer via magnetic coupling
US12879395 Abandoned US20100327661A1 (en) 2005-07-12 2010-09-10 Packaging and details of a wireless power device
US12879263 Abandoned US20110012431A1 (en) 2005-07-12 2010-09-10 Resonators for wireless power transfer
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US12896400 Abandoned US20110025131A1 (en) 2005-07-12 2010-10-01 Packaging and details of a wireless power device
US12939400 Abandoned US20110049998A1 (en) 2005-07-12 2010-11-04 Wireless delivery of power to a fixed-geometry power part
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US13163020 Abandoned US20110241618A1 (en) 2005-07-12 2011-06-17 Methods and systems for wireless power transmission
US13477459 Active 2028-06-27 US9444265B2 (en) 2005-07-12 2012-05-22 Wireless energy transfer
US13789860 Active 2026-12-20 US9509147B2 (en) 2005-07-12 2013-03-08 Wireless energy transfer
US14666683 Active US9450422B2 (en) 2005-07-12 2015-03-24 Wireless energy transfer
US15186969 Active 2026-12-25 US10097044B2 (en) 2005-07-12 2016-06-20 Wireless energy transfer

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Cited By (169)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100068998A1 (en) * 2007-02-14 2010-03-18 Emmanuel Zyambo Wireless interface
US20100123353A1 (en) * 2005-07-12 2010-05-20 Joannopoulos John D Wireless energy transfer with high-q from more than one source
US20100264747A1 (en) * 2008-09-27 2010-10-21 Hall Katherine L Wireless energy transfer converters
US20110082612A1 (en) * 2008-11-07 2011-04-07 Toyota Jidosha Kabushiki Kaisha Power feeding system for vehicle, electrically powered vehicle and power feeding apparatus for vehicle
US20110181123A1 (en) * 2008-10-09 2011-07-28 Toyota Jidosha Kabushiki Kaisha Non-contact power reception device and vehicle including the same
US20110214926A1 (en) * 2008-10-09 2011-09-08 Toyota Jidosha Kabushiki Kaisha Electrical powered vehicle
US20110231029A1 (en) * 2008-09-25 2011-09-22 Toyota Jidosha Kabushiki Kaisha Power feeding system and electrical powered vehicle
US8035255B2 (en) 2008-09-27 2011-10-11 Witricity Corporation Wireless energy transfer using planar capacitively loaded conducting loop resonators
US20110270462A1 (en) * 2008-11-14 2011-11-03 Toyota Jidosha Kabushiki Kaisha Contactless power supply system and control method thereof
US8212520B2 (en) 2008-12-24 2012-07-03 Kabushiki Kaisha Toyota Jikoshikki Resonance type non-contact charging device
US8294419B2 (en) 2008-11-21 2012-10-23 Toyota Jidosha Kabushiki Kaisha Electrical powered vehicle
US8304935B2 (en) 2008-09-27 2012-11-06 Witricity Corporation Wireless energy transfer using field shaping to reduce loss
US8310108B2 (en) 2009-04-13 2012-11-13 Nippon Soken, Inc. Non-contact electric power supplying equipment, non-contact electric power receiving device, and non-contact electric power supplying system
US8324759B2 (en) 2008-09-27 2012-12-04 Witricity Corporation Wireless energy transfer using magnetic materials to shape field and reduce loss
US8362651B2 (en) 2008-10-01 2013-01-29 Massachusetts Institute Of Technology Efficient near-field wireless energy transfer using adiabatic system variations
US8400017B2 (en) 2008-09-27 2013-03-19 Witricity Corporation Wireless energy transfer for computer peripheral applications
US8410636B2 (en) 2008-09-27 2013-04-02 Witricity Corporation Low AC resistance conductor designs
US8418823B2 (en) 2009-03-12 2013-04-16 Toyota Jidosha Kabushiki Kaisha Electrically powered vehicle
US8441154B2 (en) 2008-09-27 2013-05-14 Witricity Corporation Multi-resonator wireless energy transfer for exterior lighting
US8461722B2 (en) 2008-09-27 2013-06-11 Witricity Corporation Wireless energy transfer using conducting surfaces to shape field and improve K
US8461721B2 (en) 2008-09-27 2013-06-11 Witricity Corporation Wireless energy transfer using object positioning for low loss
US8461720B2 (en) 2008-09-27 2013-06-11 Witricity Corporation Wireless energy transfer using conducting surfaces to shape fields and reduce loss
US8466583B2 (en) 2008-09-27 2013-06-18 Witricity Corporation Tunable wireless energy transfer for outdoor lighting applications
US8471410B2 (en) 2008-09-27 2013-06-25 Witricity Corporation Wireless energy transfer over distance using field shaping to improve the coupling factor
US8476788B2 (en) 2008-09-27 2013-07-02 Witricity Corporation Wireless energy transfer with high-Q resonators using field shaping to improve K
US8482158B2 (en) 2008-09-27 2013-07-09 Witricity Corporation Wireless energy transfer using variable size resonators and system monitoring
US8487480B1 (en) 2008-09-27 2013-07-16 Witricity Corporation Wireless energy transfer resonator kit
US8552592B2 (en) 2008-09-27 2013-10-08 Witricity Corporation Wireless energy transfer with feedback control for lighting applications
US8569914B2 (en) 2008-09-27 2013-10-29 Witricity Corporation Wireless energy transfer using object positioning for improved k
US8581445B2 (en) 2010-12-01 2013-11-12 Toyota Jidosha Kabushiki Kaisha Wireless electric power feeding equipment
US8587155B2 (en) 2008-09-27 2013-11-19 Witricity Corporation Wireless energy transfer using repeater resonators
US8587153B2 (en) 2008-09-27 2013-11-19 Witricity Corporation Wireless energy transfer using high Q resonators for lighting applications
US8598743B2 (en) 2008-09-27 2013-12-03 Witricity Corporation Resonator arrays for wireless energy transfer
US8629578B2 (en) 2008-09-27 2014-01-14 Witricity Corporation Wireless energy transfer systems
US8643326B2 (en) 2008-09-27 2014-02-04 Witricity Corporation Tunable wireless energy transfer systems
US8646585B2 (en) 2008-10-09 2014-02-11 Toyota Jidosha Kabushiki Kaisha Non contact power transfer device and vehicle equipped therewith
US8655530B2 (en) 2010-04-21 2014-02-18 Toyota Jidosha Kabushiki Kaisha Parking assist device for vehicle and electrically powered vehicle including the same
US8667452B2 (en) 2011-11-04 2014-03-04 Witricity Corporation Wireless energy transfer modeling tool
US8669676B2 (en) 2008-09-27 2014-03-11 Witricity Corporation Wireless energy transfer across variable distances using field shaping with magnetic materials to improve the coupling factor
US8686598B2 (en) 2008-09-27 2014-04-01 Witricity Corporation Wireless energy transfer for supplying power and heat to a device
US8692412B2 (en) 2008-09-27 2014-04-08 Witricity Corporation Temperature compensation in a wireless transfer system
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US8692410B2 (en) 2008-09-27 2014-04-08 Witricity Corporation Wireless energy transfer with frequency hopping
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US8729737B2 (en) 2008-09-27 2014-05-20 Witricity Corporation Wireless energy transfer using repeater resonators
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US9093853B2 (en) 2008-09-27 2015-07-28 Witricity Corporation Flexible resonator attachment
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US9160203B2 (en) 2008-09-27 2015-10-13 Witricity Corporation Wireless powered television
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US9384885B2 (en) 2011-08-04 2016-07-05 Witricity Corporation Tunable wireless power architectures
US9396867B2 (en) 2008-09-27 2016-07-19 Witricity Corporation Integrated resonator-shield structures
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US9531217B2 (en) 2011-06-27 2016-12-27 Toyota Jidosha Kabushiki Kaisha Power reception device, power transmission device and power transfer system
US9533592B2 (en) 2013-09-11 2017-01-03 Toyota Jidosha Kabushiki Kaisha Vehicle
US9533591B2 (en) 2012-01-30 2017-01-03 Toyota Jidosha Kabushiki Kaisha Vehicular power reception device, power supply apparatus, and electric power transfer system
US9536655B2 (en) 2010-12-01 2017-01-03 Toyota Jidosha Kabushiki Kaisha Wireless power feeding apparatus, vehicle, and method of controlling wireless power feeding system
US9536654B2 (en) 2011-09-28 2017-01-03 Toyota Jidosha Kabushiki Kaisha Power receiving device, power transmitting device, and power transfer system
US9544683B2 (en) 2008-09-27 2017-01-10 Witricity Corporation Wirelessly powered audio devices
US9545850B2 (en) 2011-11-25 2017-01-17 Toyota Jidosha Kabushiki Kaisha Vehicle
US9559550B2 (en) 2011-02-15 2017-01-31 Toyota Jidosha Kabushiki Kaisha Contactless power receiving apparatus and vehicle incorporating same, contactless power feeding facility, method of controlling contactless power receiving apparatus, and method of controlling contactless power feeding facility
US9577449B2 (en) 2014-01-17 2017-02-21 Honda Motor Co., Ltd. Method and apparatus to align wireless charging coils
US9595378B2 (en) 2012-09-19 2017-03-14 Witricity Corporation Resonator enclosure
US9601270B2 (en) 2008-09-27 2017-03-21 Witricity Corporation Low AC resistance conductor designs
US9602168B2 (en) 2010-08-31 2017-03-21 Witricity Corporation Communication in wireless energy transfer systems
US9601266B2 (en) 2008-09-27 2017-03-21 Witricity Corporation Multiple connected resonators with a single electronic circuit
US9623759B2 (en) 2014-01-31 2017-04-18 Toyota Jidosha Kabushiki Kaisha Non-contact electric power transmission system and charging station
US9623758B2 (en) 2013-10-01 2017-04-18 Toyota Jidosha Kabushiki Kaisha Power reception device, power transmission device and vehicle
US9634733B2 (en) 2010-12-24 2017-04-25 Toyota Jidosha Kabushiki Kaisha Contactless power feeding system, vehicle, power feeding facility and method of controlling contactless power feeding system
US9637015B2 (en) 2014-01-31 2017-05-02 Toyota Jidosha Kabushiki Kaisha Non-contact electric power transmission system and charging station
US9643505B2 (en) 2013-04-26 2017-05-09 Toyota Jidosha Kabushiki Kaisha Power receiving device, power transmitting device, power transfer system, and parking assisting device
US9649947B2 (en) 2014-01-31 2017-05-16 Toyota Jidosha Kabushiki Kaisha Non-contact electric power transmission system, charging station, and vehicle
US9649946B2 (en) 2012-09-13 2017-05-16 Toyota Jidosha Kabushiki Kaisha Vehicle and contactless power supply system for adjusting impedence based on power transfer efficiency
US9673664B2 (en) 2011-10-27 2017-06-06 Toyota Jidosha Kabushiki Kaisha Wireless power reception apparatus, wireless power transmission apparatus, and wireless power transmission and reception system
US9697952B2 (en) 2011-10-27 2017-07-04 Toyota Jidosha Kabushiki Kaisha Non-contact electric power reception device, non-contact electric power transmission device, and non-contact electric power transmission and reception system
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US9721722B2 (en) 2011-10-07 2017-08-01 Toyota Jidosha Kabushiki Kaisha Power reception device, vehicle including power reception device, and power transfer system
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US9744858B2 (en) 2008-09-27 2017-08-29 Witricity Corporation System for wireless energy distribution in a vehicle
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US9768622B2 (en) 2014-04-22 2017-09-19 Toyota Jidosha Kabushiki Kaisha Non-contact power transmitting and receiving system
US9780573B2 (en) 2014-02-03 2017-10-03 Witricity Corporation Wirelessly charged battery system
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US9802497B2 (en) 2011-11-24 2017-10-31 Toyota Jidosha Kabushiki Kaisha Electric power transmission device, vehicle, and non-contact electric power transmission and reception system
US9825473B2 (en) 2014-08-04 2017-11-21 Toyota Jidosha Kabushiki Kaisha Contactless power transfer system
US9834103B2 (en) 2014-01-31 2017-12-05 Toyota Jidosha Kabushiki Kaisha Non-contact electric power transmission system
US9837860B2 (en) 2014-05-05 2017-12-05 Witricity Corporation Wireless power transmission systems for elevators
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US9842687B2 (en) 2014-04-17 2017-12-12 Witricity Corporation Wireless power transfer systems with shaped magnetic components
US9842688B2 (en) 2014-07-08 2017-12-12 Witricity Corporation Resonator balancing in wireless power transfer systems
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US9929721B2 (en) 2015-10-14 2018-03-27 Witricity Corporation Phase and amplitude detection in wireless energy transfer systems
US9948145B2 (en) 2011-07-08 2018-04-17 Witricity Corporation Wireless power transfer for a seat-vest-helmet system
US9944193B2 (en) 2013-11-20 2018-04-17 Toyota Jidosha Kabushiki Kaisha Vehicle including electric power transmission and reception unit
US9952266B2 (en) 2014-02-14 2018-04-24 Witricity Corporation Object detection for wireless energy transfer systems
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US9956884B2 (en) 2015-08-07 2018-05-01 Toyota Jidosha Kabushiki Kaisha Vehicle
US9966796B2 (en) 2015-08-07 2018-05-08 Toyota Jidosha Kabushiki Kaisha Power reception device and power transmission device
US9963040B2 (en) 2012-09-13 2018-05-08 Toyota Jidosha Kabushiki Kaisha Non-contact power supply system, and power transmission device and vehicle used therein
US9969281B2 (en) 2011-11-22 2018-05-15 Toyota Jidosha Kabushiki Kaisha Vehicle and power transfer system
US9981564B2 (en) 2014-07-04 2018-05-29 Toyota Jidosha Kabushiki Kaisha Power transmission device and power reception device
US10017065B2 (en) 2014-04-04 2018-07-10 Toyota Jidosha Kabushiki Kaisha Power reception device and vehicle including the same
US10020688B2 (en) 2015-07-17 2018-07-10 Toyota Jidosha Kabushiki Kaisha Contactless power transmission device and power transfer system
US10018744B2 (en) 2014-05-07 2018-07-10 Witricity Corporation Foreign object detection in wireless energy transfer systems
US10029576B2 (en) 2013-09-11 2018-07-24 Toyota Jidosha Kabushiki Kaisha Power receiving device, power transmitting device, and vehicle
US10052963B2 (en) 2013-12-25 2018-08-21 Toyota Jidosha Kabushiki Kaisha Contactless power transfer system and method of controlling the same
US10063104B2 (en) 2016-02-08 2018-08-28 Witricity Corporation PWM capacitor control
US10063110B2 (en) 2015-10-19 2018-08-28 Witricity Corporation Foreign object detection in wireless energy transfer systems
US10065514B2 (en) 2015-02-27 2018-09-04 Toyota Jidosha Kabushiki Kaisha Power transfer system
US10075019B2 (en) 2015-11-20 2018-09-11 Witricity Corporation Voltage source isolation in wireless power transfer systems
US10097043B2 (en) 2015-07-21 2018-10-09 Toyota Jidosha Kabushiki Kaisha Contactless power transmission device and power transfer system
US10110064B2 (en) 2015-07-10 2018-10-23 Toyota Jidosha Kabushiki Kaisha Contactless power transmission device and power transfer system
US10122216B2 (en) 2014-04-25 2018-11-06 Toyota Jidosha Kabushiki Kaisha Power transmitting device and power receiving device
US10124685B2 (en) 2013-11-18 2018-11-13 Toyota Jidosha Kabushiki Kaisha Power reception device having a coil formed like a flat plate
US10135287B2 (en) 2015-08-04 2018-11-20 Toyota Jidosha Kabushiki Kaisha Vehicle wireless power transfer using metal member with high permeability to improve charging efficiency
US10141784B2 (en) 2015-03-11 2018-11-27 Toyota Jidosha Kabushiki Kaisha Power receiving device and power transmitting device
US10141788B2 (en) 2015-10-22 2018-11-27 Witricity Corporation Dynamic tuning in wireless energy transfer systems

Families Citing this family (353)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9090170B2 (en) * 2008-08-26 2015-07-28 Alex Mashinsky Self-charging electric vehicle and aircraft and wireless energy distribution system
US8447234B2 (en) * 2006-01-18 2013-05-21 Qualcomm Incorporated Method and system for powering an electronic device via a wireless link
US9130602B2 (en) 2006-01-18 2015-09-08 Qualcomm Incorporated Method and apparatus for delivering energy to an electrical or electronic device via a wireless link
US7952322B2 (en) 2006-01-31 2011-05-31 Mojo Mobility, Inc. Inductive power source and charging system
US8169185B2 (en) 2006-01-31 2012-05-01 Mojo Mobility, Inc. System and method for inductive charging of portable devices
US7948208B2 (en) 2006-06-01 2011-05-24 Mojo Mobility, Inc. Power source, charging system, and inductive receiver for mobile devices
JP4791949B2 (en) * 2006-12-22 2011-10-12 株式会社東芝 Non-volatile semiconductor memory
JP5331307B2 (en) * 2007-01-24 2013-10-30 オリンパス株式会社 A capsule endoscope, and the capsule endoscope system
US9774086B2 (en) 2007-03-02 2017-09-26 Qualcomm Incorporated Wireless power apparatus and methods
US9124120B2 (en) 2007-06-11 2015-09-01 Qualcomm Incorporated Wireless power system and proximity effects
US9634730B2 (en) * 2007-07-09 2017-04-25 Qualcomm Incorporated Wireless energy transfer using coupled antennas
CN103187629B (en) * 2007-08-09 2016-08-24 高通股份有限公司 Increase factor of the resonator q
WO2009023646A3 (en) * 2007-08-13 2009-04-23 Nigelpower Llc Long range low frequency resonator and materials
KR100863972B1 (en) * 2007-09-13 2008-10-16 삼성에스디아이 주식회사 Cathode ray tube
EP2188867A4 (en) * 2007-09-13 2014-12-10 Qualcomm Inc Antennas for wireless power applications
WO2009036405A1 (en) 2007-09-13 2009-03-19 Nigelpower, Llc Maximizing power yield from wireless power magnetic resonators
CN104283332B (en) 2007-09-17 2018-08-07 高通股份有限公司 Wireless power magnetic resonators in high efficiency and power transfer
WO2009039113A1 (en) 2007-09-17 2009-03-26 Nigel Power, Llc Transmitters and receivers for wireless energy transfer
KR20100072264A (en) * 2007-09-19 2010-06-30 퀄컴 인코포레이티드 Maximizing power yield from wireless power magnetic resonators
CN101842963B (en) 2007-10-11 2014-05-28 高通股份有限公司 Wireless power transfer using magneto mechanical systems
JP4453741B2 (en) 2007-10-25 2010-04-21 トヨタ自動車株式会社 Electric vehicles and vehicle power supply system
US8729734B2 (en) * 2007-11-16 2014-05-20 Qualcomm Incorporated Wireless power bridge
CN107086677A (en) * 2007-11-28 2017-08-22 高通股份有限公司 Wireless power range increase using parasitic antennas
US9128687B2 (en) * 2008-01-10 2015-09-08 Qualcomm Incorporated Wireless desktop IT environment
US8294300B2 (en) * 2008-01-14 2012-10-23 Qualcomm Incorporated Wireless powering and charging station
US8487479B2 (en) 2008-02-24 2013-07-16 Qualcomm Incorporated Ferrite antennas for wireless power transfer
US8344552B2 (en) 2008-02-27 2013-01-01 Qualcomm Incorporated Antennas and their coupling characteristics for wireless power transfer via magnetic coupling
US8855554B2 (en) * 2008-03-05 2014-10-07 Qualcomm Incorporated Packaging and details of a wireless power device
US8421267B2 (en) * 2008-03-10 2013-04-16 Qualcomm, Incorporated Packaging and details of a wireless power device
US8629576B2 (en) 2008-03-28 2014-01-14 Qualcomm Incorporated Tuning and gain control in electro-magnetic power systems
US20100038970A1 (en) 2008-04-21 2010-02-18 Nigel Power, Llc Short Range Efficient Wireless Power Transfer
JP4544338B2 (en) * 2008-04-28 2010-09-15 ソニー株式会社 Power transmission device, the power reception device, the power transmission method, a program, and the power transmission system
US8878393B2 (en) * 2008-05-13 2014-11-04 Qualcomm Incorporated Wireless power transfer for vehicles
US8965461B2 (en) 2008-05-13 2015-02-24 Qualcomm Incorporated Reverse link signaling via receive antenna impedance modulation
US8076801B2 (en) 2008-05-14 2011-12-13 Massachusetts Institute Of Technology Wireless energy transfer, including interference enhancement
US8466654B2 (en) * 2008-07-08 2013-06-18 Qualcomm Incorporated Wireless high power transfer under regulatory constraints
WO2010009429A1 (en) * 2008-07-17 2010-01-21 Qualcomm Incorporated Adaptive matching and tuning of hf wireless power transmit antenna
US8740266B2 (en) 2008-07-18 2014-06-03 Patrick E. Keller Sentinel event reducing safety knobs
US8278784B2 (en) * 2008-07-28 2012-10-02 Qualcomm Incorporated Wireless power transmission for electronic devices
US8111042B2 (en) * 2008-08-05 2012-02-07 Broadcom Corporation Integrated wireless resonant power charging and communication channel
US7893564B2 (en) * 2008-08-05 2011-02-22 Broadcom Corporation Phased array wireless resonant power delivery system
US8023269B2 (en) * 2008-08-15 2011-09-20 Siemens Energy, Inc. Wireless telemetry electronic circuit board for high temperature environments
US8901880B2 (en) * 2008-08-19 2014-12-02 Qualcomm Incorporated Wireless power transmission for portable wireless power charging
US20100081379A1 (en) * 2008-08-20 2010-04-01 Intel Corporation Wirelessly powered speaker
US20100045114A1 (en) * 2008-08-20 2010-02-25 Sample Alanson P Adaptive wireless power transfer apparatus and method thereof
US8299652B2 (en) 2008-08-20 2012-10-30 Intel Corporation Wireless power transfer apparatus and method thereof
US8432070B2 (en) * 2008-08-25 2013-04-30 Qualcomm Incorporated Passive receivers for wireless power transmission
US8947041B2 (en) * 2008-09-02 2015-02-03 Qualcomm Incorporated Bidirectional wireless power transmission
US8421274B2 (en) 2008-09-12 2013-04-16 University Of Pittsburgh-Of The Commonwealth System Of Higher Education Wireless energy transfer system
US8532724B2 (en) * 2008-09-17 2013-09-10 Qualcomm Incorporated Transmitters for wireless power transmission
JP4743244B2 (en) * 2008-09-18 2011-08-10 トヨタ自動車株式会社 Non-contact power receiving apparatus
JP5152338B2 (en) * 2008-09-19 2013-02-27 トヨタ自動車株式会社 Non-contact charging device and the non-contact power receiving apparatus
US20120248887A1 (en) * 2008-09-27 2012-10-04 Kesler Morris P Multi-resonator wireless energy transfer for sensors
US20120242159A1 (en) * 2008-09-27 2012-09-27 Herbert Toby Lou Multi-resonator wireless energy transfer for appliances
US20110043049A1 (en) * 2008-09-27 2011-02-24 Aristeidis Karalis Wireless energy transfer with high-q resonators using field shaping to improve k
US20110074346A1 (en) * 2009-09-25 2011-03-31 Hall Katherine L Vehicle charger safety system and method
US20120086867A1 (en) * 2008-09-27 2012-04-12 Kesler Morris P Modular upgrades for wirelessly powered televisions
CA2752573A1 (en) * 2009-02-13 2010-08-19 Witricity Corporation Wireless energy transfer in lossy environments
US20120119569A1 (en) * 2008-09-27 2012-05-17 Aristeidis Karalis Multi-resonator wireless energy transfer inside vehicles
US20100277121A1 (en) * 2008-09-27 2010-11-04 Hall Katherine L Wireless energy transfer between a source and a vehicle
US20120228952A1 (en) * 2008-09-27 2012-09-13 Hall Katherine L Tunable wireless energy transfer for appliances
WO2010038297A1 (en) * 2008-10-02 2010-04-08 トヨタ自動車株式会社 Self-resonant coil, contactless power transferring apparatus, and vehicle
JP5375032B2 (en) * 2008-11-04 2013-12-25 株式会社豊田自動織機 Method of designing a non-contact power transmission apparatus and the non-contact power transmission apparatus
KR101440591B1 (en) 2008-11-17 2014-09-17 삼성전자 주식회사 Apparatus of wireless power transmission using high Q near magnetic field resonator
US8929957B2 (en) * 2008-11-21 2015-01-06 Qualcomm Incorporated Reduced jamming between receivers and wireless power transmitters
JP4759610B2 (en) * 2008-12-01 2011-08-31 トヨタ自動車株式会社 Non-contact power transmission apparatus
CN102239622A (en) * 2008-12-09 2011-11-09 丰田自动车株式会社 Non-contact power transmission apparatus and power transmission method using a non-contact power transmission apparatus
JP5238472B2 (en) * 2008-12-16 2013-07-17 株式会社日立製作所 Power transmission device, and a power receiving device
JP5285418B2 (en) * 2008-12-24 2013-09-11 株式会社豊田自動織機 Resonance type non-contact power supply device
US8497658B2 (en) 2009-01-22 2013-07-30 Qualcomm Incorporated Adaptive power control for wireless charging of devices
DE102009007464A1 (en) * 2009-02-04 2010-08-05 Infineon Technologies Ag Detecting means, A method for determining a transmission parameter, energy transfer means and method for wireless transmission of energy
JP2010183814A (en) * 2009-02-09 2010-08-19 Toyota Industries Corp Non-contact power transmitter
JP5262785B2 (en) * 2009-02-09 2013-08-14 株式会社豊田自動織機 Non-contact power transmission apparatus
US8854224B2 (en) 2009-02-10 2014-10-07 Qualcomm Incorporated Conveying device information relating to wireless charging
US20100201201A1 (en) * 2009-02-10 2010-08-12 Qualcomm Incorporated Wireless power transfer in public places
US9312924B2 (en) 2009-02-10 2016-04-12 Qualcomm Incorporated Systems and methods relating to multi-dimensional wireless charging
US20100201312A1 (en) 2009-02-10 2010-08-12 Qualcomm Incorporated Wireless power transfer for portable enclosures
JP4849142B2 (en) * 2009-02-27 2012-01-11 ソニー株式会社 Power supply and a power transmission system
JP5585098B2 (en) * 2009-03-06 2014-09-10 日産自動車株式会社 A contactless power supply apparatus and method
WO2010106636A1 (en) 2009-03-17 2010-09-23 富士通株式会社 Wireless power supply system
CN105291991A (en) * 2009-03-17 2016-02-03 富士通株式会社 Wireless power supply system
JP5621203B2 (en) * 2009-03-30 2014-11-12 富士通株式会社 The wireless power supply system, the wireless power supply method
WO2010116441A1 (en) 2009-03-30 2010-10-14 富士通株式会社 Wireless power supply system, wireless power transmission device, and wireless power receiving device
JP5417941B2 (en) * 2009-03-31 2014-02-19 富士通株式会社 The power transmission device
JP5417942B2 (en) * 2009-03-31 2014-02-19 富士通株式会社 Power transmitting device, transmitting and receiving apparatus and transmission method
JP5353376B2 (en) * 2009-03-31 2013-11-27 富士通株式会社 Wireless power device, the wireless power receiving method
JP5515368B2 (en) * 2009-03-31 2014-06-11 富士通株式会社 The wireless power supply method and the wireless power supply system
JP5365306B2 (en) * 2009-03-31 2013-12-11 富士通株式会社 The wireless power supply system
US9692485B1 (en) 2009-03-31 2017-06-27 Ronald C. Krosky Wireless energy reception management
JP5689587B2 (en) * 2009-03-31 2015-03-25 富士通株式会社 Power transmission device
US9132250B2 (en) * 2009-09-03 2015-09-15 Breathe Technologies, Inc. Methods, systems and devices for non-invasive ventilation including a non-sealing ventilation interface with an entrainment port and/or pressure feature
US9096375B2 (en) 2009-04-10 2015-08-04 Symbotic, LLC Storage and retrieval system
US9825490B2 (en) * 2009-04-14 2017-11-21 Sony Corporation Power transmission device, power transmission method, power reception device, power reception method, and power transmission system
US9013141B2 (en) * 2009-04-28 2015-04-21 Qualcomm Incorporated Parasitic devices for wireless power transfer
CN108215914A (en) * 2009-05-12 2018-06-29 奥克兰联合服务有限公司 Inductive power transfer apparatus and electric autocycle charger including same
EP2431213B1 (en) 2009-05-14 2018-03-14 Toyota Jidosha Kabushiki Kaisha Vehicle charging unit
JP2011029799A (en) * 2009-07-23 2011-02-10 Sony Corp Contactless power supplying communication apparatus, contactless power receiving communication device, power-supplying communication control method, and power receiving communication control method
CN102474133A (en) 2009-07-23 2012-05-23 富士通株式会社 Power transmission device, wireless power supply system, and wireless power supply device
US20110031817A1 (en) * 2009-08-06 2011-02-10 Electronics And Telecommunications Research Institute Rectifying antenna array
WO2011019088A3 (en) 2009-08-13 2011-09-09 Panasonic Corporation Wireless power transmission unit and power generator and power generation system with the wireless power unit
CN102013736B (en) 2009-09-03 2013-10-16 Tdk株式会社 Wireless power feeder and wireless power transmission system
US20110057891A1 (en) * 2009-09-10 2011-03-10 Qualcomm Incorporated Wireless power display device
US8579789B1 (en) 2009-09-23 2013-11-12 Leviticus Cardio Ltd. Endovascular ventricular assist device, using the mathematical objective and principle of superposition
JP5499955B2 (en) * 2009-10-05 2014-05-21 Tdk株式会社 Wireless power supply apparatus and the wireless power transmission system
US8829726B2 (en) 2010-07-02 2014-09-09 Tdk Corporation Wireless power feeder and wireless power transmission system
US8729736B2 (en) 2010-07-02 2014-05-20 Tdk Corporation Wireless power feeder and wireless power transmission system
JP5577896B2 (en) 2009-10-07 2014-08-27 Tdk株式会社 Wireless power supply apparatus and the wireless power transmission system
US20110084782A1 (en) 2009-10-09 2011-04-14 Hiroshi Kanno Electromagnetic filter and electronic device having same
CN102481855B (en) * 2009-10-14 2014-08-20 松下电器产业株式会社 Electric machine and power supply system having battery pack
KR101679580B1 (en) * 2009-10-16 2016-11-29 삼성전자주식회사 Wireless Power Transmission Device, Wireless Power Transmission Controlling Device and Wireless Power Transmission Method
JP5476917B2 (en) * 2009-10-16 2014-04-23 Tdk株式会社 The wireless power supply apparatus, the wireless power receiving apparatus and wireless power transmission system
JP5471283B2 (en) * 2009-10-19 2014-04-16 Tdk株式会社 The wireless power supply apparatus, the wireless power receiving apparatus and wireless power transmission system
US8772977B2 (en) 2010-08-25 2014-07-08 Tdk Corporation Wireless power feeder, wireless power transmission system, and table and table lamp using the same
JP5664019B2 (en) * 2009-10-28 2015-02-04 Tdk株式会社 The wireless power supply apparatus, the wireless power transmission system and the table and table lamp utilizing them
US8829727B2 (en) 2009-10-30 2014-09-09 Tdk Corporation Wireless power feeder, wireless power transmission system, and table and table lamp using the same
JP5664018B2 (en) 2009-10-30 2015-02-04 Tdk株式会社 The wireless power supply apparatus, the wireless power transmission system and the table and table lamp utilizing them
US8466660B2 (en) * 2009-11-06 2013-06-18 Toyota Motor Engg. & Mfg. North America, Inc. Wireless energy transfer antennas and energy charging systems
JP5641891B2 (en) 2009-11-13 2014-12-17 パナソニック株式会社 Charging and power supply system for a vehicle
JP5909714B2 (en) * 2009-11-13 2016-04-27 パナソニックIpマネジメント株式会社 Charging and power supply system for a vehicle
JP2013511255A (en) 2009-11-17 2013-03-28 アップル インコーポレイテッド Use of the wireless power of the local computing environment
US8829729B2 (en) 2010-08-18 2014-09-09 Tdk Corporation Wireless power feeder, wireless power receiver, and wireless power transmission system
US8729735B2 (en) 2009-11-30 2014-05-20 Tdk Corporation Wireless power feeder, wireless power receiver, and wireless power transmission system
US20110133568A1 (en) * 2009-12-03 2011-06-09 Bingnan Wang Wireless Energy Transfer with Metamaterials
US9461505B2 (en) 2009-12-03 2016-10-04 Mitsubishi Electric Research Laboratories, Inc. Wireless energy transfer with negative index material
US20110133567A1 (en) * 2009-12-03 2011-06-09 Koon Hoo Teo Wireless Energy Transfer with Negative Index Material
US20110133565A1 (en) * 2009-12-03 2011-06-09 Koon Hoo Teo Wireless Energy Transfer with Negative Index Material
US20110133566A1 (en) * 2009-12-03 2011-06-09 Koon Hoo Teo Wireless Energy Transfer with Negative Material
CN102668323B (en) 2009-12-16 2016-08-03 富士通株式会社 Magnetic resonance power transmitting means, power receiving apparatus and magnetic resonance
US9081246B2 (en) * 2009-12-22 2015-07-14 View, Inc. Wireless powered electrochromic windows
EP2518862A1 (en) * 2009-12-25 2012-10-31 Kabushiki Kaisha Toshiba Wireless power transmission device and power receiving device
KR101702914B1 (en) * 2009-12-29 2017-02-06 삼성전자주식회사 Reflection power management apparatus
US8415833B2 (en) * 2009-12-29 2013-04-09 Mitsubishi Electric Research Laboratories, Inc. Wireless energy transfer with negative index material
US20110156487A1 (en) * 2009-12-30 2011-06-30 Koon Hoo Teo Wireless Energy Transfer with Energy Relays
JP2011142748A (en) * 2010-01-07 2011-07-21 Sony Corp Wireless power supply system
US8384247B2 (en) * 2010-01-13 2013-02-26 Mitsubishi Electric Research Laboratories, Inc. Wireless energy transfer to moving devices
US8674549B2 (en) * 2010-01-13 2014-03-18 Mitsubishi Electric Research Laboratories, Inc. System and method for energy transfer
KR101114587B1 (en) * 2010-01-28 2012-03-05 주식회사 팬택 System, the terminal device, the management server and the wireless power transmission apparatus for transmitting and receiving
KR101167382B1 (en) * 2010-02-08 2012-07-19 삼성전기주식회사 wireless energy transmission structure
KR101438294B1 (en) 2010-02-10 2014-09-04 후지쯔 가부시끼가이샤 Resonance frequency control method, power transmission device, and power reception device for magnetic-resonant-coupling type power transmission system
KR20130016247A (en) * 2010-03-04 2013-02-14 예다 리서치 앤드 디벨럽먼트 캄파니 리미티드 Efficient robust wireless energy transfer
CN102195366B (en) * 2010-03-19 2014-03-12 Tdk株式会社 Wireless power feeder, and wireless power transmission system
WO2011122003A1 (en) 2010-03-30 2011-10-06 パナソニック株式会社 Wireless power transmission system
JP2011234605A (en) 2010-04-05 2011-11-17 Tdk Corp Wireless power reception device and wireless power transmission system
JP5750583B2 (en) 2010-04-07 2015-07-22 パナソニックIpマネジメント株式会社 Wireless power transmission system
KR101718723B1 (en) * 2010-04-08 2017-03-22 삼성전자주식회사 Laptop computer system with wireless power transform function
KR20110114925A (en) * 2010-04-14 2011-10-20 삼성전자주식회사 3-dimension glasses, 3d display apparatus and system for charging 3-dimension glasses
KR101167401B1 (en) * 2010-04-30 2012-07-19 숭실대학교산학협력단 Apparatus for transmitting and receiving wireless energy using meta material structure having zero refractive index
CN102439820B (en) 2010-05-03 2016-08-03 松下知识产权经营株式会社 Generator, the power generation system and the wireless power transmission apparatus
US8427014B2 (en) 2010-05-11 2013-04-23 The Invention Science Fund I, Llc System including wearable power receiver and wearable power-output device
US8476863B2 (en) * 2010-05-17 2013-07-02 Mitchell Andrew Paasch Energy storage and charging system for a vehicle
JP5146488B2 (en) * 2010-05-26 2013-02-20 トヨタ自動車株式会社 Power supply system and a vehicle
US8994221B2 (en) * 2010-06-01 2015-03-31 University Of Maryland Method and system for long range wireless power transfer
US8890470B2 (en) 2010-06-11 2014-11-18 Mojo Mobility, Inc. System for wireless power transfer that supports interoperability, and multi-pole magnets for use therewith
US8952573B2 (en) 2010-06-30 2015-02-10 Panasonic Intellectual Property Management Co., Ltd. Power generator and power generation system
US8917511B2 (en) 2010-06-30 2014-12-23 Panasonic Corporation Wireless power transfer system and power transmitting/receiving device with heat dissipation structure
US8970070B2 (en) 2010-07-02 2015-03-03 Panasonic Intellectual Property Management Co., Ltd. Wireless power transmission system
JP5573439B2 (en) 2010-07-09 2014-08-20 Tdk株式会社 Wireless power supply apparatus, a light source cartridge and wireless lighting systems
JP5736991B2 (en) 2010-07-22 2015-06-17 Tdk株式会社 Wireless power supply apparatus and the wireless power transmission system
KR101395256B1 (en) * 2010-07-23 2014-05-16 한국전자통신연구원 Wireless energy transfer apparatus and making method therefor
JP5530848B2 (en) * 2010-07-28 2014-06-25 トヨタ自動車株式会社 Coil unit, contactless power transmission apparatus, a contactless power receiving apparatus, a vehicle and the non-contact power feeding system
KR101441453B1 (en) * 2010-08-25 2014-09-18 한국전자통신연구원 Apparatus and method for reducing electric field and radiation field in magnetic resonant coupling coils or magnetic induction device for wireless energy transfer
WO2012044103A3 (en) * 2010-09-30 2012-08-23 Lg Innotek Co., Ltd. Energy transmission apparatus and method
WO2012046453A1 (en) 2010-10-08 2012-04-12 パナソニック株式会社 Wireless power transmission device, and power generation device provided with wireless power transmission device
WO2012046452A1 (en) 2010-10-08 2012-04-12 パナソニック株式会社 Power generation system and power generation unit
US8901775B2 (en) 2010-12-10 2014-12-02 Everheart Systems, Inc. Implantable wireless power system
JP5564412B2 (en) * 2010-12-10 2014-07-30 株式会社日立製作所 Wireless power transmission system, the power transmission device, and the power receiving device
US9496924B2 (en) 2010-12-10 2016-11-15 Everheart Systems, Inc. Mobile wireless power system
US9058928B2 (en) 2010-12-14 2015-06-16 Tdk Corporation Wireless power feeder and wireless power transmission system
US20120191517A1 (en) 2010-12-15 2012-07-26 Daffin Jr Mack Paul Prepaid virtual card
US9008884B2 (en) 2010-12-15 2015-04-14 Symbotic Llc Bot position sensing
US9475649B2 (en) 2010-12-15 2016-10-25 Symbolic, LLC Pickface builder for storage and retrieval systems
US8998554B2 (en) 2010-12-15 2015-04-07 Symbotic Llc Multilevel vertical conveyor platform guides
US9054745B2 (en) 2010-12-22 2015-06-09 Electronics And Telecommunications Research Institute Apparatus for transmitting/receiving energy using a resonance structure in an energy system
CN103262387B (en) 2010-12-24 2016-08-17 丰田自动车株式会社 Non-contact charging methods and systems, vehicles, and non-contact charging management apparatus
US9143010B2 (en) 2010-12-28 2015-09-22 Tdk Corporation Wireless power transmission system for selectively powering one or more of a plurality of receivers
US8669677B2 (en) 2010-12-28 2014-03-11 Tdk Corporation Wireless power feeder, wireless power receiver, and wireless power transmission system
US8800738B2 (en) 2010-12-28 2014-08-12 Tdk Corporation Wireless power feeder and wireless power receiver
US8664803B2 (en) 2010-12-28 2014-03-04 Tdk Corporation Wireless power feeder, wireless power receiver, and wireless power transmission system
KR101171938B1 (en) * 2010-12-30 2012-08-07 전자부품연구원 Multi-node wireless power transmission system and charging method therof using magnetic resonance induction
KR101221049B1 (en) 2010-12-30 2013-01-21 전자부품연구원 Charging method of multi-node wireless charging system using magnetic field communication
CN103443883B (en) * 2011-01-14 2016-10-12 香港城市大学 Wireless power transmission apparatus and method for
US9178369B2 (en) 2011-01-18 2015-11-03 Mojo Mobility, Inc. Systems and methods for providing positioning freedom, and support of different voltages, protocols, and power levels in a wireless power system
US10115520B2 (en) 2011-01-18 2018-10-30 Mojo Mobility, Inc. Systems and method for wireless power transfer
US9496732B2 (en) 2011-01-18 2016-11-15 Mojo Mobility, Inc. Systems and methods for wireless power transfer
US9077209B2 (en) 2011-01-20 2015-07-07 Panasonic Intellectual Property Management Co., Ltd. Power generation system, power generating module, module fixing device and method for installing power generation system
US8669678B2 (en) 2011-02-22 2014-03-11 Tdk Corporation Wireless power feeder, wireless power receiver, and wireless power transmission system
US8742627B2 (en) 2011-03-01 2014-06-03 Tdk Corporation Wireless power feeder
US9356449B2 (en) 2011-03-01 2016-05-31 Tdk Corporation Wireless power receiver, wireless power transmission system, and power controller
US9035500B2 (en) 2011-03-01 2015-05-19 Tdk Corporation Wireless power feeder, wireless power receiver, and wireless power transmission system, and coil
US8922064B2 (en) 2011-03-01 2014-12-30 Tdk Corporation Wireless power feeder, wireless power receiver, and wireless power transmission system, and coil
US8953810B2 (en) 2011-03-03 2015-02-10 Cochlear Limited Synchronization in a bilateral auditory prosthesis system
US9042996B2 (en) 2011-03-10 2015-05-26 Cochlear Limited Wireless communications in medical devices
US8213074B1 (en) 2011-03-16 2012-07-03 Soladigm, Inc. Onboard controller for multistate windows
US8970069B2 (en) 2011-03-28 2015-03-03 Tdk Corporation Wireless power receiver and wireless power transmission system
US8570923B2 (en) * 2011-04-20 2013-10-29 Holophasec Pty. Ltd. Resonant communications transceiver method and apparatus
US9620995B2 (en) 2011-04-26 2017-04-11 Panasonic Intellectual Property Management Co., Ltd. Wireless power transmission system
CN103038993B (en) 2011-05-26 2016-04-20 松下电器产业株式会社 AC conversion circuit, the AC conversion method and a recording medium
KR101586135B1 (en) 2011-05-31 2016-01-21 애플 인크. Combining power from multiple resonance magnetic receivers in resonance magnetic power system
US9199545B2 (en) 2011-06-01 2015-12-01 Samsung Electronics Co., Ltd. Method and apparatus for controlling wireless power transmission
DE102011103439B3 (en) * 2011-06-07 2012-08-30 Audi Ag Motor vehicle with a store for electric energy, which is charged inductively via a coil, the housing comprises a device for detecting damage
US9640316B2 (en) 2011-06-07 2017-05-02 Sekisui Chemical Co., Ltd. Contactless power transfer system, contactless power transfer device, contactless power transfer program and contactless power transfer method
US20120326523A1 (en) 2011-06-22 2012-12-27 Noriyuki Fukushima Wireless power feeder, wireless power receiver, and wireless power transmission system
US9030161B2 (en) 2011-06-27 2015-05-12 Board Of Regents, The University Of Texas System Wireless power transmission
JP2013013204A (en) * 2011-06-28 2013-01-17 Toshiba Corp Wireless power transmission system, power transmission device and power reception device
WO2013002437A1 (en) * 2011-06-29 2013-01-03 엘지전자 주식회사 Method for avoiding a signal collision in a one-way communication in a wireless power transmission
US20130007949A1 (en) * 2011-07-08 2013-01-10 Witricity Corporation Wireless energy transfer for person worn peripherals
US9379571B2 (en) 2011-07-11 2016-06-28 Delphi Technologies, Inc. Electrical charging system having energy coupling arrangement for wireless energy transmission therebetween
WO2013009881A3 (en) 2011-07-11 2013-06-20 Vascor, Inc. Transcutaneous power transmission and communication for implanted heart assist and other devices
KR101809470B1 (en) 2011-07-28 2017-12-15 삼성전자주식회사 Wireless power transmission system, method and apparatus for resonance frequency tracking in wireless power transmission system
KR101239289B1 (en) * 2011-08-03 2013-03-06 한양대학교 산학협력단 Wireless power transfer system
JP5798407B2 (en) 2011-08-09 2015-10-21 Fdk株式会社 Contactless rechargeable secondary battery
US9642958B2 (en) 2011-08-19 2017-05-09 Leviticus Cardio Ltd. Coplanar wireless energy transfer
US9343224B2 (en) 2011-08-19 2016-05-17 Leviticus Cardio Ltd. Coplanar energy transfer
US8979728B2 (en) 2011-08-22 2015-03-17 Leviticus Cardio Ltd. Safe energy transfer
CA2788895A1 (en) * 2011-09-07 2013-03-07 Solace Power Inc. Wireless electric field power transmission system and method
US10033225B2 (en) 2012-09-07 2018-07-24 Solace Power Inc. Wireless electric field power transmission system, transmitter and receiver therefor and method of wirelessly transferring power
US9213932B2 (en) 2011-09-27 2015-12-15 Samsung Electronics Co., Ltd. Communication system using wireless power
US9008328B2 (en) 2011-09-28 2015-04-14 Tdk Corporation Headphone, headphone stand and headphone system
US9356474B2 (en) 2011-09-28 2016-05-31 Tdk Corporation Wireless power feeder and wireless power transmission system
KR20130035057A (en) * 2011-09-29 2013-04-08 한국전자통신연구원 Wireless power transfer and recieve device
KR20130035905A (en) * 2011-09-30 2013-04-09 삼성전자주식회사 Method for wireless charging and apparatus for the same
US9142998B2 (en) 2011-10-03 2015-09-22 The Board Of Trustees Of The Leland Stanford Junior University Wireless energy transfer
JP5512628B2 (en) 2011-10-19 2014-06-04 東芝テック株式会社 Power transmission device, the power transmission device, the power receiving device and a power transmission method
JP5885239B2 (en) * 2011-10-20 2016-03-15 トヨタ自動車株式会社 The power receiving device, the power transmission device and a power transmission system
KR101831993B1 (en) * 2011-11-18 2018-02-26 삼성전자주식회사 Apparatus and method for controlling amount of charging current for wireless power receiver
WO2013076937A1 (en) 2011-11-22 2013-05-30 パナソニック株式会社 Ac conversion circuit
US9196419B2 (en) 2011-11-29 2015-11-24 Panasonic Intellectual Property Management Co., Ltd. Wireless electric power transmission apparatus
US9224533B2 (en) 2011-11-29 2015-12-29 Panasonic Intellectual Property Management Co., Ltd. Wireless electric power transmission apparatus
US9197101B2 (en) 2011-11-29 2015-11-24 Panasonic Intellectual Property Management Co., Ltd. Wireless electric power transmission apparatus
US9431856B2 (en) * 2012-01-09 2016-08-30 Pabellon, Inc. Power transmission
US9496731B2 (en) 2012-01-20 2016-11-15 Samsung Electronics Co., Ltd Apparatus and method for transmitting wireless power by using resonant coupling and system for the same
JP6074745B2 (en) 2012-01-25 2017-02-08 パナソニックIpマネジメント株式会社 Wireless power transmission system and transmission apparatus
KR20130099576A (en) 2012-02-29 2013-09-06 한국전자통신연구원 Apparatus for transferring power
CN103296782A (en) * 2012-02-29 2013-09-11 朱斯忠 Resonance derivative ring
US9722447B2 (en) 2012-03-21 2017-08-01 Mojo Mobility, Inc. System and method for charging or powering devices, such as robots, electric vehicles, or other mobile devices or equipment
US20130271069A1 (en) 2012-03-21 2013-10-17 Mojo Mobility, Inc. Systems and methods for wireless power transfer
US9796280B2 (en) 2012-03-23 2017-10-24 Hevo Inc. Systems and mobile application for electric wireless charging stations
KR20130107955A (en) * 2012-03-23 2013-10-02 삼성전자주식회사 Wireless power transmission system and method that controls resonance frequency and increases coupling efficiency
WO2013146929A1 (en) 2012-03-28 2013-10-03 富士通株式会社 Wireless power transmission system and wireless power transmission method
CN104521100B (en) 2012-04-10 2017-12-12 松下知识产权经营株式会社 The wireless power transmission apparatus, power supply apparatus and a power receiving means
US20130300205A1 (en) * 2012-05-09 2013-11-14 Samsung Electronics Co., Ltd. Method and apparatus for 3d orientation-free wireless power transfer
US8827889B2 (en) * 2012-05-21 2014-09-09 University Of Washington Through Its Center For Commercialization Method and system for powering implantable devices
WO2014006895A1 (en) 2012-07-05 2014-01-09 パナソニック株式会社 Wireless power transmission device, wireless power sending device and power receiving device
WO2014014388A1 (en) * 2012-07-19 2014-01-23 Atamanov Alexander Viktorovich Wireless charging system for low-power consumers of electrical energy
US20150180241A1 (en) * 2012-07-27 2015-06-25 Thoratec Corporation Computer modeling for resonant power transfer systems
US9287040B2 (en) 2012-07-27 2016-03-15 Thoratec Corporation Self-tuning resonant power transfer systems
WO2014018973A1 (en) 2012-07-27 2014-01-30 Thoratec Corporation Resonant power transmission coils and systems
US9825471B2 (en) 2012-07-27 2017-11-21 Thoratec Corporation Resonant power transfer systems with protective algorithm
EP2878061A4 (en) 2012-07-27 2016-03-02 Thoratec Corp Thermal management for implantable wireless power transfer systems
US9805863B2 (en) 2012-07-27 2017-10-31 Thoratec Corporation Magnetic power transmission utilizing phased transmitter coil arrays and phased receiver coil arrays
GB201215152D0 (en) 2012-08-24 2012-10-10 Imp Innovations Ltd Maximising DC to load efficiency for inductive power transfer
EP2888732A4 (en) * 2012-08-27 2016-12-21 Rensselaer Polytech Inst Method and apparatus for acoustical power transfer and communication
US9106095B2 (en) * 2012-08-29 2015-08-11 Google Inc. Inductive charging keyboard
KR20140034982A (en) 2012-09-11 2014-03-21 삼성전자주식회사 Apparatus and method for controlling resonator of wireless power transfer system
US20140083769A1 (en) * 2012-09-24 2014-03-27 Schlumberger Technology Corporation Coiled Tube Drilling Bottom Hole Assembly Having Wireless Power And Data Connection
US9997291B2 (en) 2012-09-28 2018-06-12 Denso Wave Incorporated Wireless power supply apparatus, filter unit and power supply apparatus for robot using the filter unit
US20140091636A1 (en) * 2012-10-02 2014-04-03 Witricity Corporation Wireless power transfer
US9261870B2 (en) 2012-10-30 2016-02-16 Vikrant Sharma Control system for power transmission within a structure
US9768643B2 (en) 2012-11-02 2017-09-19 Panasonic Intellectual Property Management Co., Ltd. Wireless power transmission system capable of continuing power transmission while suppressing heatup of foreign objects
US9627929B2 (en) 2012-11-02 2017-04-18 Panasonic Intellectual Property Management Co., Ltd. Wireless power transfer system for wirelessly transferring electric power in noncontact manner by utilizing resonant magnetic field coupling
US8845510B2 (en) 2012-12-11 2014-09-30 Leviticus Cardio Ltd. Flexible galvanic primary and non galvanic secondary coils for wireless coplanar energy transfer (CET)
KR20140077591A (en) 2012-12-14 2014-06-24 삼성전자주식회사 Wireless power transmission device, wireless power reception device, wireless power transmission system and wireless power transmission method
KR20140089187A (en) 2013-01-04 2014-07-14 삼성전자주식회사 Wireless power reception device and wireless power transmission system
JP5836287B2 (en) 2013-01-07 2015-12-24 東芝テック株式会社 Power transmission device
JP6282398B2 (en) 2013-02-19 2018-02-21 矢崎総業株式会社 Electromagnetic induction coil
US9912031B2 (en) 2013-03-07 2018-03-06 Cpg Technologies, Llc Excitation and use of guided surface wave modes on lossy media
US9910144B2 (en) 2013-03-07 2018-03-06 Cpg Technologies, Llc Excitation and use of guided surface wave modes on lossy media
US20140292274A1 (en) 2013-03-15 2014-10-02 Symbotic, LLC Rover charging system
US9680310B2 (en) 2013-03-15 2017-06-13 Thoratec Corporation Integrated implantable TETS housing including fins and coil loops
EP2984731A4 (en) 2013-03-15 2016-11-30 Thoratec Corp Malleable tets coil with improved anatomical fit
US9481517B2 (en) 2013-03-15 2016-11-01 Symbotic, LLC Multiposition lift
WO2014147819A1 (en) * 2013-03-22 2014-09-25 トヨタ自動車株式会社 Vehicle, and contactless power supply system
JP5688549B2 (en) 2013-04-10 2015-03-25 パナソニック インテレクチュアル プロパティ コーポレーション オブアメリカPanasonic Intellectual Property Corporation of America Coil module and electronic equipment
US9837846B2 (en) 2013-04-12 2017-12-05 Mojo Mobility, Inc. System and method for powering or charging receivers or devices having small surface areas or volumes
US9496746B2 (en) 2013-05-15 2016-11-15 The Regents Of The University Of Michigan Wireless power transmission for battery charging
US9431169B2 (en) * 2013-06-07 2016-08-30 Qualcomm Incorporated Primary power supply tuning network for two coil device and method of operation
US9601267B2 (en) 2013-07-03 2017-03-21 Qualcomm Incorporated Wireless power transmitter with a plurality of magnetic oscillators
US9191757B2 (en) 2013-07-11 2015-11-17 Starkey Laboratories, Inc. Hearing aid with inductively coupled electromagnetic resonator antenna
JP5889250B2 (en) 2013-07-12 2016-03-22 東芝テック株式会社 Power transmission device, the power transmission device and a power receiving apparatus for power transmission apparatus
WO2015015771A1 (en) 2013-07-31 2015-02-05 パナソニック株式会社 Wireless power-transfer system and power-transmission device
US20150054344A1 (en) * 2013-08-26 2015-02-26 The University Of Hong Kong Wireless Power Transfer System
ES2535562B2 (en) 2013-10-11 2016-05-25 Univ Politècnica De València Device wireless power transfer
CN203786283U (en) * 2013-10-14 2014-08-20 英飞凌科技股份有限公司 Self-testing system for magnetism
US10038340B2 (en) 2013-10-21 2018-07-31 Electronics And Telecommunications Research Institute Wireless power transmission method and apparatus for improving spectrum efficiency and space efficiency based on impedance matching and relay resonance
WO2015060781A1 (en) 2013-10-24 2015-04-30 Harald Merkel Method and arrangement for wireless energy transfer
US9793579B2 (en) 2013-11-08 2017-10-17 Leviticus Cardio Ltd. Batteries for use in implantable medical devices
WO2015070200A1 (en) 2013-11-11 2015-05-14 Thoratec Corporation Resonant power transfer systems with communications
US9855437B2 (en) 2013-11-11 2018-01-02 Tc1 Llc Hinged resonant power transfer coil
CN103915913B (en) * 2014-03-31 2017-01-11 华南理工大学 For Fractional series - parallel resonant wireless power transmission system
US9793720B2 (en) 2014-04-16 2017-10-17 The Regents Of The University Of Michigan Wireless power transfer using multiple near-field plates
US10114120B2 (en) 2014-04-16 2018-10-30 The Regents Of The University Of Michigan Unidirectional near-field focusing using near-field plates
US9837830B2 (en) 2014-04-25 2017-12-05 Electronics And Telecommunications Research Institute Wireless power transmitting method and apparatus using dual-loop in-phase feeding
US9380682B2 (en) 2014-06-05 2016-06-28 Steelcase Inc. Environment optimization for space based on presence and activities
US9852388B1 (en) 2014-10-03 2017-12-26 Steelcase, Inc. Method and system for locating resources and communicating within an enterprise
US9955318B1 (en) 2014-06-05 2018-04-24 Steelcase Inc. Space guidance and management system and method
US9842685B2 (en) 2014-07-21 2017-12-12 Mitsubishi Electric Research Laboratories, Inc. Artificial magnetic structures for wireless power transfer
US9855376B2 (en) 2014-07-25 2018-01-02 Minnetronix, Inc. Power scaling
US9780571B2 (en) 2014-08-28 2017-10-03 Motorola Solutions, Inc. Methods and systems for providing a ballast load for a magnetic resonant power supply
US9941566B2 (en) 2014-09-10 2018-04-10 Cpg Technologies, Llc Excitation and use of guided surface wave modes on lossy media
US9893402B2 (en) 2014-09-11 2018-02-13 Cpg Technologies, Llc Superposition of guided surface waves on lossy media
US9887556B2 (en) 2014-09-11 2018-02-06 Cpg Technologies, Llc Chemically enhanced isolated capacitance
US10001553B2 (en) 2014-09-11 2018-06-19 Cpg Technologies, Llc Geolocation with guided surface waves
US9882397B2 (en) 2014-09-11 2018-01-30 Cpg Technologies, Llc Guided surface wave transmission of multiple frequencies in a lossy media
US10027116B2 (en) 2014-09-11 2018-07-17 Cpg Technologies, Llc Adaptation of polyphase waveguide probes
US9887587B2 (en) 2014-09-11 2018-02-06 Cpg Technologies, Llc Variable frequency receivers for guided surface wave transmissions
US9960470B2 (en) 2014-09-11 2018-05-01 Cpg Technologies, Llc Site preparation for guided surface wave transmission in a lossy media
US10079573B2 (en) 2014-09-11 2018-09-18 Cpg Technologies, Llc Embedding data on a power signal
US10084223B2 (en) 2014-09-11 2018-09-25 Cpg Technologies, Llc Modulated guided surface waves
US9887557B2 (en) 2014-09-11 2018-02-06 Cpg Technologies, Llc Hierarchical power distribution
US10033198B2 (en) 2014-09-11 2018-07-24 Cpg Technologies, Llc Frequency division multiplexing for wireless power providers
US9859707B2 (en) 2014-09-11 2018-01-02 Cpg Technologies, Llc Simultaneous multifrequency receive circuits
US10101444B2 (en) 2014-09-11 2018-10-16 Cpg Technologies, Llc Remote surface sensing using guided surface wave modes on lossy media
US10074993B2 (en) 2014-09-11 2018-09-11 Cpg Technologies, Llc Simultaneous transmission and reception of guided surface waves
US9985694B2 (en) 2014-09-23 2018-05-29 Motorola Solutions, Inc. Methods and systems for contactless battery discharging
US9583874B2 (en) 2014-10-06 2017-02-28 Thoratec Corporation Multiaxial connector for implantable devices
GB2533695B (en) * 2014-12-23 2018-02-21 Intel Corp Coil topology for wireless charging
US9685148B2 (en) 2015-01-02 2017-06-20 Fishman Transducers, Inc. Method and device for wireless power source for an instrument
ES2542278B1 (en) * 2015-02-23 2016-01-22 Carlos Andrés MARTÍNEZ CASAIS multi-device wireless charger
US9923385B2 (en) 2015-06-02 2018-03-20 Cpg Technologies, Llc Excitation and use of guided surface waves
US20160379753A1 (en) * 2015-06-29 2016-12-29 Korea Advanced Institute Of Science And Technology Method and system for layout optimization of secondary coil for wireless power transfer
CA2992507A1 (en) * 2015-07-17 2017-01-26 The Governors Of The University Of Alberta Method and system for wireless and single conductor power transmission
US9887585B2 (en) 2015-09-08 2018-02-06 Cpg Technologies, Llc Changing guided surface wave transmissions to follow load conditions
US9857402B2 (en) 2015-09-08 2018-01-02 CPG Technologies, L.L.C. Measuring and reporting power received from guided surface waves
US9921256B2 (en) 2015-09-08 2018-03-20 Cpg Technologies, Llc Field strength monitoring for optimal performance
US9997040B2 (en) 2015-09-08 2018-06-12 Cpg Technologies, Llc Global emergency and disaster transmission
JP2018534899A (en) 2015-09-08 2018-11-22 シーピージー テクノロジーズ、 エルエルシーCpg Technologies, Llc Long-distance transmission of offshore power
US10031208B2 (en) 2015-09-09 2018-07-24 Cpg Technologies, Llc Object identification system and method
CN108352725A (en) 2015-09-09 2018-07-31 Cpg技术有限责任公司 Guided surface waveguide probes
US9887558B2 (en) 2015-09-09 2018-02-06 Cpg Technologies, Llc Wired and wireless power distribution coexistence
US10062944B2 (en) 2015-09-09 2018-08-28 CPG Technologies, Inc. Guided surface waveguide probes
US9882436B2 (en) 2015-09-09 2018-01-30 Cpg Technologies, Llc Return coupled wireless power transmission
US9927477B1 (en) 2015-09-09 2018-03-27 Cpg Technologies, Llc Object identification system and method
US10027131B2 (en) 2015-09-09 2018-07-17 CPG Technologies, Inc. Classification of transmission
US9916485B1 (en) 2015-09-09 2018-03-13 Cpg Technologies, Llc Method of managing objects using an electromagnetic guided surface waves over a terrestrial medium
US10063095B2 (en) 2015-09-09 2018-08-28 CPG Technologies, Inc. Deterring theft in wireless power systems
US9885742B2 (en) 2015-09-09 2018-02-06 Cpg Technologies, Llc Detecting unauthorized consumption of electrical energy
US9496921B1 (en) 2015-09-09 2016-11-15 Cpg Technologies Hybrid guided surface wave communication
US10033197B2 (en) 2015-09-09 2018-07-24 Cpg Technologies, Llc Object identification system and method
US9973037B1 (en) 2015-09-09 2018-05-15 Cpg Technologies, Llc Object identification system and method
WO2017044299A1 (en) 2015-09-09 2017-03-16 Cpg Technologies, Llc. Load shedding in a guided surface wave power delivery system
US10103452B2 (en) 2015-09-10 2018-10-16 Cpg Technologies, Llc Hybrid phased array transmission
EP3342024A1 (en) 2015-09-10 2018-07-04 CPG Technologies, LLC Mobile guided surface waveguide probes and receivers
EP3338341A1 (en) 2015-09-11 2018-06-27 CPG Technologies, LLC Global electrical power multiplication
CN108352612A (en) 2015-09-11 2018-07-31 Cpg技术有限责任公司 Enhanced guided surface waveguide probe
US20170085097A1 (en) * 2015-09-23 2017-03-23 Intel Corporation Tuning in a Wireless Power Transmitter
US10135285B2 (en) 2015-11-30 2018-11-20 The Boeing Company Wireless power for vehicular passenger seats
US20170179731A1 (en) * 2015-12-22 2017-06-22 Intel Corporation Wireless charging coil placement for reduced field exposure
US20170182903A1 (en) * 2015-12-26 2017-06-29 Intel Corporation Technologies for wireless charging of electric vehicles
US10069328B2 (en) 2016-04-06 2018-09-04 Powersphyr Inc. Intelligent multi-mode wireless power system
CN105811311A (en) * 2016-05-18 2016-07-27 三峡大学 Guide rail system used for inspection robot for power transmission line with functions of charging inspection robot and enabling inspection robot to pass through tower
US9921726B1 (en) 2016-06-03 2018-03-20 Steelcase Inc. Smart workstation method and system
WO2018157917A1 (en) 2017-02-28 2018-09-07 Toyota Motor Europe Method of aligning electronic circuits and electronic alignment system
US10128697B1 (en) 2017-05-01 2018-11-13 Hevo, Inc. Detecting and deterring foreign objects and living objects at wireless charging stations

Citations (72)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US645576A (en) * 1897-09-02 1900-03-20 Nikola Tesla System of transmission of electrical energy.
US787412A (en) * 1900-05-16 1905-04-18 Nikola Tesla Art of transmitting electrical energy through the natural mediums.
US3517350A (en) * 1969-07-07 1970-06-23 Bell Telephone Labor Inc Energy translating device
US4088999A (en) * 1976-05-21 1978-05-09 Nasa RF beam center location method and apparatus for power transmission system
US5118997A (en) * 1991-08-16 1992-06-02 General Electric Company Dual feedback control for a high-efficiency class-d power amplifier circuit
US5216402A (en) * 1992-01-22 1993-06-01 Hughes Aircraft Company Separable inductive coupler
US5493691A (en) * 1993-12-23 1996-02-20 Barrett; Terence W. Oscillator-shuttle-circuit (OSC) networks for conditioning energy in higher-order symmetry algebraic topological forms and RF phase conjugation
US5528113A (en) * 1993-10-21 1996-06-18 Boys; John T. Inductive power pick-up coils
US5898579A (en) * 1992-05-10 1999-04-27 Auckland Uniservices Limited Non-contact power distribution system
US6184651B1 (en) * 2000-03-20 2001-02-06 Motorola, Inc. Contactless battery charger with wireless control link
US20020032471A1 (en) * 2000-09-06 2002-03-14 Loftin Scott M. Low-power, high-modulation-index amplifier for use in battery-powered device
US6515878B1 (en) * 1997-08-08 2003-02-04 Meins Juergen G. Method and apparatus for supplying contactless power
US20030038641A1 (en) * 2000-03-02 2003-02-27 Guntram Scheible Proximity sensor
US20030062980A1 (en) * 2000-03-09 2003-04-03 Guntram Scheible Configuration for producing electrical power from a magnetic field
US20030062794A1 (en) * 2001-09-15 2003-04-03 Guntram Scheible Magnetic field production system, and configuration for wire-free supply of a large number of sensors and/or actuators using a magnetic field production system
US20040000974A1 (en) * 2002-06-26 2004-01-01 Koninklijke Philips Electronics N.V. Planar resonator for wireless power transfer
US20040100338A1 (en) * 2002-11-13 2004-05-27 Clark Roger L. Oscillator module incorporating looped-stub resonator
US20040113847A1 (en) * 2002-12-12 2004-06-17 Yihong Qi Antenna with near-field radiation control
US20050007067A1 (en) * 1999-06-21 2005-01-13 Baarman David W. Vehicle interface
US20050085873A1 (en) * 2003-10-17 2005-04-21 Gord John C. Method and apparatus for efficient power/data transmission
US20050093475A1 (en) * 1999-06-21 2005-05-05 Kuennen Roy W. Inductively coupled ballast circuit
US20050104064A1 (en) * 2002-03-01 2005-05-19 John Hegarty Semiconductor photodetector
US20050116650A1 (en) * 1999-06-21 2005-06-02 Baarman David W. Method of manufacturing a lamp assembly
US20050122058A1 (en) * 1999-06-21 2005-06-09 Baarman David W. Inductively powered apparatus
US20050127866A1 (en) * 2003-12-11 2005-06-16 Alistair Hamilton Opportunistic power supply charge system for portable unit
US20060022636A1 (en) * 2004-07-30 2006-02-02 Kye Systems Corporation Pulse frequency modulation for induction charge device
US20060061323A1 (en) * 2002-10-28 2006-03-23 Cheng Lily K Contact-less power transfer
US20060132045A1 (en) * 2004-12-17 2006-06-22 Baarman David W Heating system and heater
US20070013483A1 (en) * 2005-07-15 2007-01-18 Allflex U.S.A. Inc. Passive dynamic antenna tuning circuit for a radio frequency identification reader
US20070021140A1 (en) * 2005-07-22 2007-01-25 Keyes Marion A Iv Wireless power transmission systems and methods
US20070064406A1 (en) * 2003-09-08 2007-03-22 Beart Pilgrim G W Inductive power transfer units having flux shields
US20070096875A1 (en) * 2005-10-02 2007-05-03 Paul Waterhouse Radio tag and system
US20070145830A1 (en) * 2005-12-27 2007-06-28 Mobilewise, Inc. System and method for contact free transfer of power
US20080012569A1 (en) * 2005-05-21 2008-01-17 Hall David R Downhole Coils
US20080014897A1 (en) * 2006-01-18 2008-01-17 Cook Nigel P Method and apparatus for delivering energy to an electrical or electronic device via a wireless link
US20080030415A1 (en) * 2006-08-02 2008-02-07 Schlumberger Technology Corporation Flexible Circuit for Downhole Antenna
US20080067874A1 (en) * 2006-09-14 2008-03-20 Ryan Tseng Method and apparatus for wireless power transmission
US7375493B2 (en) * 2003-12-12 2008-05-20 Microsoft Corporation Inductive battery charger
US7375492B2 (en) * 2003-12-12 2008-05-20 Microsoft Corporation Inductively charged battery pack
US7378817B2 (en) * 2003-12-12 2008-05-27 Microsoft Corporation Inductive power adapter
US7382636B2 (en) * 2005-10-14 2008-06-03 Access Business Group International Llc System and method for powering a load
US7385357B2 (en) * 1999-06-21 2008-06-10 Access Business Group International Llc Inductively coupled ballast circuit
US20090010028A1 (en) * 2005-08-16 2009-01-08 Access Business Group International Llc Inductive power supply, remote device powered by inductive power supply and method for operating same
US20090015075A1 (en) * 2007-07-09 2009-01-15 Nigel Power, Llc Wireless Energy Transfer Using Coupled Antennas
US20090033564A1 (en) * 2007-08-02 2009-02-05 Nigel Power, Llc Deployable Antennas for Wireless Power
US7492247B2 (en) * 2003-03-19 2009-02-17 Sew-Eurodrive Gmbh & Co. Kg Transmitter head and system for contactless energy transmission
US20090045772A1 (en) * 2007-06-11 2009-02-19 Nigelpower, Llc Wireless Power System and Proximity Effects
US20090051224A1 (en) * 2007-03-02 2009-02-26 Nigelpower, Llc Increasing the q factor of a resonator
US20090058189A1 (en) * 2007-08-13 2009-03-05 Nigelpower, Llc Long range low frequency resonator and materials
US20090067198A1 (en) * 2007-08-29 2009-03-12 David Jeffrey Graham Contactless power supply
US20090072628A1 (en) * 2007-09-13 2009-03-19 Nigel Power, Llc Antennas for Wireless Power applications
US20090072629A1 (en) * 2007-09-17 2009-03-19 Nigel Power, Llc High Efficiency and Power Transfer in Wireless Power Magnetic Resonators
US20090072627A1 (en) * 2007-03-02 2009-03-19 Nigelpower, Llc Maximizing Power Yield from Wireless Power Magnetic Resonators
US20090079268A1 (en) * 2007-03-02 2009-03-26 Nigel Power, Llc Transmitters and receivers for wireless energy transfer
US20090085408A1 (en) * 2007-09-01 2009-04-02 Maquet Gmbh & Co. Kg Apparatus and method for wireless energy and/or data transmission between a source device and at least one target device
US20090085706A1 (en) * 2007-09-28 2009-04-02 Access Business Group International Llc Printed circuit board coil
US7514818B2 (en) * 2005-10-26 2009-04-07 Matsushita Electric Works, Ltd. Power supply system
US7518267B2 (en) * 2003-02-04 2009-04-14 Access Business Group International Llc Power adapter for a remote device
US20090096413A1 (en) * 2006-01-31 2009-04-16 Mojo Mobility, Inc. System and method for inductive charging of portable devices
US20090102292A1 (en) * 2007-09-19 2009-04-23 Nigel Power, Llc Biological Effects of Magnetic Power Transfer
US7525283B2 (en) * 2002-05-13 2009-04-28 Access Business Group International Llc Contact-less power transfer
US20090108997A1 (en) * 2007-10-31 2009-04-30 Intermec Ip Corp. System, devices, and method for energizing passive wireless data communication devices
US20090108679A1 (en) * 2007-10-30 2009-04-30 Ati Technologies Ulc Wireless energy transfer
US20090127937A1 (en) * 2007-11-16 2009-05-21 Nigelpower, Llc Wireless Power Bridge
US20090134712A1 (en) * 2007-11-28 2009-05-28 Nigel Power Llc Wireless Power Range Increase Using Parasitic Antennas
US20090146892A1 (en) * 2007-12-07 2009-06-11 Sony Ericsson Mobile Communications Japan, Inc. Non-contact wireless communication apparatus, method of adjusting resonance frequency of non-contact wireless communication antenna, and mobile terminal apparatus
US20090153273A1 (en) * 2007-12-14 2009-06-18 Darfon Electronics Corp. Energy transferring system and method thereof
US20090160261A1 (en) * 2007-12-19 2009-06-25 Nokia Corporation Wireless energy transfer
US20100038970A1 (en) * 2008-04-21 2010-02-18 Nigel Power, Llc Short Range Efficient Wireless Power Transfer
US20100096934A1 (en) * 2005-07-12 2010-04-22 Joannopoulos John D Wireless energy transfer with high-q similar resonant frequency resonators
US20100117456A1 (en) * 2005-07-12 2010-05-13 Aristeidis Karalis Applications of wireless energy transfer using coupled antennas
US20100148589A1 (en) * 2008-10-01 2010-06-17 Hamam Rafif E Efficient near-field wireless energy transfer using adiabatic system variations

Family Cites Families (342)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US646576A (en) * 1899-09-20 1900-04-03 Latham W Greenleaf Mortising-machine.
GB190508200A (en) 1905-04-17 1906-04-17 Nikola Tesla Improvements relating to the Transmission of Electrical Energy.
US1119732A (en) 1907-05-04 1914-12-01 Nikola Tesla Apparatus for transmitting electrical energy.
US2133494A (en) 1936-10-24 1938-10-18 Harry F Waters Wirelessly energized electrical appliance
BE482157A (en) 1938-12-13
US3535543A (en) 1969-05-01 1970-10-20 Nasa Microwave power receiving antenna
GB1303835A (en) 1970-01-30 1973-01-24
US3871176A (en) 1973-03-08 1975-03-18 Combustion Eng Large sodium valve actuator
US4095998A (en) 1976-09-30 1978-06-20 The United States Of America As Represented By The Secretary Of The Army Thermoelectric voltage generator
JPS5374078A (en) * 1976-12-14 1978-07-01 Bridgestone Tire Co Ltd Device for warning pressure reducing of inner pressure of tire
US4280129A (en) * 1978-09-09 1981-07-21 Wells Donald H Variable mutual transductance tuned antenna
DE3043441A1 (en) * 1980-11-18 1982-06-03 Deutsche Forsch Luft Raumfahrt Power transfer system - has transformer allowing position data update inside SOS buoy on board ship
US4450431A (en) * 1981-05-26 1984-05-22 Hochstein Peter A Condition monitoring system (tire pressure)
US4441210A (en) 1981-09-18 1984-04-03 Hochmair Erwin S Transcutaneous signal transmission system and methods
US4588978A (en) * 1984-06-21 1986-05-13 Transensory Devices, Inc. Remote switch-sensing system
JPH0644683B2 (en) 1984-12-30 1994-06-08 原田工業株式会社 Transmission line coupler for antenna
JPH043521Y2 (en) 1985-03-25 1992-02-04
US4679560A (en) 1985-04-02 1987-07-14 Board Of Trustees Of The Leland Stanford Junior University Wide band inductive transdermal power and data link
ES2008655T3 (en) 1987-07-31 1994-02-01 Texas Instruments Deutschland Gmbh Response transmission arrangement (transponder).
DE3815114A1 (en) * 1988-05-04 1989-11-16 Bosch Gmbh Robert Apparatus for transmission and evaluation of measurement signals for the reifendurck of motor vehicles
DE3824972A1 (en) 1988-07-22 1989-01-12 Roland Hiering Illumination of christmas trees, decorations and artwork
JPH0297005A (en) * 1988-10-03 1990-04-09 Tokyo Cosmos Electric Co Ltd Variable inductance
JPH069781Y2 (en) 1989-01-23 1994-03-16 マツダ株式会社 Work supporting device of slicing machine
JP2820706B2 (en) 1989-03-02 1998-11-05 株式会社デンソー Power supply having a coil for electromagnetic coupling
US5034658A (en) 1990-01-12 1991-07-23 Roland Hierig Christmas-tree, decorative, artistic and ornamental object illumination apparatus
US5027709A (en) * 1990-04-26 1991-07-02 Slagle Glenn B Magnetic induction mine arming, disarming and simulation system
JPH0750508Y2 (en) 1990-08-30 1995-11-15 ナショナル住宅産業株式会社 Kasagi mounting structure
JPH04265875A (en) 1991-02-21 1992-09-22 Seiko Instr Inc Plane type gradiometer
US5957956A (en) 1994-06-21 1999-09-28 Angeion Corp Implantable cardioverter defibrillator having a smaller mass
US5293308A (en) 1991-03-26 1994-03-08 Auckland Uniservices Limited Inductive power distribution system
NL9101590A (en) 1991-09-20 1993-04-16 Ericsson Radio Systems Bv A system for charging a rechargeable battery of a portable unit in a rack.
US5341083A (en) * 1991-09-27 1994-08-23 Electric Power Research Institute, Inc. Contactless battery charging system
GB2262634B (en) * 1991-12-18 1995-07-12 Apple Computer Power connection scheme
US5229652A (en) 1992-04-20 1993-07-20 Hough Wayne E Non-contact data and power connector for computer based modules
US6738697B2 (en) 1995-06-07 2004-05-18 Automotive Technologies International Inc. Telematics system for vehicle diagnostics
DE4216590A1 (en) * 1992-05-20 1993-11-25 Basf Ag Chlorethylsulfonylbenzaldehyde
US5467718A (en) * 1992-07-20 1995-11-21 Daifuku Co., Ltd. Magnetic levitation transport system with non-contact inductive power supply and battery charging
FR2695266B1 (en) * 1992-09-02 1994-09-30 Cableco Sa Together to recharge the accumulator batteries of an electric motor vehicle.
US5437057A (en) * 1992-12-03 1995-07-25 Xerox Corporation Wireless communications using near field coupling
US5287112A (en) * 1993-04-14 1994-02-15 Texas Instruments Incorporated High speed read/write AVI system
GB9310545D0 (en) 1993-05-21 1993-07-07 Era Patents Ltd Power coupling
JP3207294B2 (en) 1993-06-02 2001-09-10 株式会社安川電機 Universal hydraulic device
JP3409145B2 (en) * 1993-07-26 2003-05-26 九州日立マクセル株式会社 Small electrical equipment
JPH0750508A (en) 1993-08-06 1995-02-21 Fujitsu Ltd Antenna module
US5541604A (en) 1993-09-03 1996-07-30 Texas Instruments Deutschland Gmbh Transponders, Interrogators, systems and methods for elimination of interrogator synchronization requirement
US5408209A (en) 1993-11-02 1995-04-18 Hughes Aircraft Company Cooled secondary coils of electric automobile charging transformer
US5565763A (en) 1993-11-19 1996-10-15 Lockheed Martin Corporation Thermoelectric method and apparatus for charging superconducting magnets
US6459218B2 (en) 1994-07-13 2002-10-01 Auckland Uniservices Limited Inductively powered lamp unit
US5522856A (en) 1994-09-20 1996-06-04 Vitatron Medical, B.V. Pacemaker with improved shelf storage capacity
JPH08191259A (en) 1995-01-11 1996-07-23 Sony Chem Corp Transmitter-receiver for contactless ic card system
US5710413A (en) 1995-03-29 1998-01-20 Minnesota Mining And Manufacturing Company H-field electromagnetic heating system for fusion bonding
US5697956A (en) 1995-06-02 1997-12-16 Pacesetter, Inc. Implantable stimulation device having means for optimizing current drain
JP3288048B2 (en) 1995-06-16 2002-06-04 ダイセル化学工業株式会社 Operative and unactuated screening method for a gas generator for an air bag in the vehicle disposal process
US5703461A (en) * 1995-06-28 1997-12-30 Kabushiki Kaisha Toyoda Jidoshokki Seisakusho Inductive coupler for electric vehicle charger
US5703950A (en) * 1995-06-30 1997-12-30 Intermec Corporation Method and apparatus for controlling country specific frequency allocation
US5630835A (en) * 1995-07-24 1997-05-20 Cardiac Control Systems, Inc. Method and apparatus for the suppression of far-field interference signals for implantable device data transmission systems
EP0788212B1 (en) 1996-01-30 2002-04-17 Sumitomo Wiring Systems, Ltd. Connection system and connection method for an electric automotive vehicle
JP3761001B2 (en) 1995-11-20 2006-03-29 ソニー株式会社 Non-contact type information card and ic
EP0782214B1 (en) * 1995-12-22 2004-10-06 Texas Instruments France Ring antennas for resonant cicuits
JPH09182323A (en) 1995-12-28 1997-07-11 Rohm Co Ltd Non-contact type electric power transmission device
US6066163A (en) 1996-02-02 2000-05-23 John; Michael Sasha Adaptive brain stimulation method and system
US6225800B1 (en) 1996-03-26 2001-05-01 Forschungszentrum Jülich GmbH Arrangement for coupling an RF-squid magnetometer to a superconductive tank circuit
DE19614455A1 (en) 1996-04-12 1997-10-16 Philips Patentverwaltung A method of operating a system comprising a base station and a so-contact coupled transponder as well as for suitable system
US6108579A (en) 1996-04-15 2000-08-22 Pacesetter, Inc. Battery monitoring apparatus and method for programmers of cardiac stimulating devices
JPH09298847A (en) 1996-04-30 1997-11-18 Sony Corp Non-contact charger
US5926949A (en) 1996-05-30 1999-07-27 Commscope, Inc. Of North Carolina Method of making coaxial cable
US6028429A (en) 1996-07-17 2000-02-22 Fonar Corporation Composite MRI antenna with reduced stray capacitance
US5821728A (en) 1996-07-22 1998-10-13 Schwind; John P. Armature induction charging of moving electric vehicle batteries
JPH1092673A (en) * 1996-07-26 1998-04-10 Tdk Corp Non-contact power transmission device
US5836943A (en) 1996-08-23 1998-11-17 Team Medical, L.L.C. Electrosurgical generator
US5742471A (en) 1996-11-25 1998-04-21 The Regents Of The University Of California Nanostructure multilayer dielectric materials for capacitors and insulators
JPH10164837A (en) 1996-11-26 1998-06-19 Sony Corp Power supply
US6317338B1 (en) 1997-05-06 2001-11-13 Auckland Uniservices Limited Power supply for an electroluminescent display
US7068991B2 (en) 1997-05-09 2006-06-27 Parise Ronald J Remote power recharge for electronic equipment
US6176433B1 (en) 1997-05-15 2001-01-23 Hitachi, Ltd. Reader/writer having coil arrangements to restrain electromagnetic field intensity at a distance
US6101300A (en) 1997-06-09 2000-08-08 Massachusetts Institute Of Technology High efficiency channel drop filter with absorption induced on/off switching and modulation
JPH1125238A (en) 1997-07-04 1999-01-29 Kokusai Electric Co Ltd Ic card
JP3113842B2 (en) 1997-08-25 2000-12-04 株式会社移動体通信先端技術研究所 filter
JPH1175329A (en) 1997-08-29 1999-03-16 Hitachi Ltd Non-contact type ic card system
US6167309A (en) 1997-09-15 2000-12-26 Cardiac Pacemakers, Inc. Method for monitoring end of life for battery
US5993996A (en) 1997-09-16 1999-11-30 Inorganic Specialists, Inc. Carbon supercapacitor electrode materials
DE19746919A1 (en) 1997-10-24 1999-05-06 Daimler Chrysler Ag Electrical transmission device
JP3840765B2 (en) 1997-11-21 2006-11-01 神鋼電機株式会社 Primary feeding side power supply in the non-contact power feeding conveyor system
JPH11188113A (en) 1997-12-26 1999-07-13 Handa Yasunobu Power transmission system, power transmission method and electric stimulation device provided with the power transmission system
JPH11285156A (en) 1998-03-30 1999-10-15 Nippon Electric Ind Co Ltd Contactless charger
US5999308A (en) 1998-04-01 1999-12-07 Massachusetts Institute Of Technology Methods and systems for introducing electromagnetic radiation into photonic crystals
US5891180A (en) 1998-04-29 1999-04-06 Medtronic Inc. Interrogation of an implantable medical device using audible sound communication
DE19845065A1 (en) 1998-05-15 1999-11-25 Siemens Ag Contactless data transmission arrangement
JP2000031706A (en) 1998-05-27 2000-01-28 Ace Technol Co Ltd Band-pass filter provided with dielectric resonator
US5986895A (en) 1998-06-05 1999-11-16 Astec International Limited Adaptive pulse width modulated resonant Class-D converter
US6047214A (en) 1998-06-09 2000-04-04 North Carolina State University System and method for powering, controlling, and communicating with multiple inductively-powered devices
US6255635B1 (en) 1998-07-10 2001-07-03 Ameritherm, Inc. System and method for providing RF power to a load
WO2000024456A8 (en) 1998-10-27 2000-08-17 Richard P Phillips Transcutaneous energy transmission system with full wave class e rectifier
JP2000148932A (en) 1998-11-13 2000-05-30 Hitachi Ltd Reader or/and writer, and ic card system using them
CN1184208C (en) 1998-11-27 2005-01-12 巴斯福股份公司 Substituted benzimidazoles and their prepn. and use
JP4019531B2 (en) 1998-12-01 2007-12-12 ソニー株式会社 Information communication system, the communication function built device, information communication method
US6631072B1 (en) 1998-12-05 2003-10-07 Energy Storage Systems Pty Ltd Charge storage device
US6615074B2 (en) 1998-12-22 2003-09-02 University Of Pittsburgh Of The Commonwealth System Of Higher Education Apparatus for energizing a remote station and related method
JP5021119B2 (en) 1999-03-24 2012-09-05 セカンド サイト メディカル プロダクツ インコーポレイテッド Artificial color prostheses of the retina for the color vision recovery
FR2792135B1 (en) 1999-04-07 2001-11-02 St Microelectronics Sa Operating in very close complage an electromagnetic transponder system has
FR2792134B1 (en) 1999-04-07 2001-06-22 St Microelectronics Sa Detection distance between an electromagnetic transponder and a terminal
US6252762B1 (en) 1999-04-21 2001-06-26 Telcordia Technologies, Inc. Rechargeable hybrid battery/supercapacitor system
US6127799A (en) 1999-05-14 2000-10-03 Gte Internetworking Incorporated Method and apparatus for wireless powering and recharging
US7212414B2 (en) * 1999-06-21 2007-05-01 Access Business Group International, Llc Adaptive inductive power supply
US7522878B2 (en) 1999-06-21 2009-04-21 Access Business Group International Llc Adaptive inductive power supply with communication
CN1922700A (en) 2003-02-04 2007-02-28 通达商业集团国际公司 Inductive coil assembly
US6436299B1 (en) * 1999-06-21 2002-08-20 Amway Corporation Water treatment system with an inductively coupled ballast
US6673250B2 (en) * 1999-06-21 2004-01-06 Access Business Group International Llc Radio frequency identification system for a fluid treatment system
US6232841B1 (en) 1999-07-01 2001-05-15 Rockwell Science Center, Llc Integrated tunable high efficiency power amplifier
US6207887B1 (en) 1999-07-07 2001-03-27 Hi-2 Technology, Inc. Miniature milliwatt electric power generator
FR2796781A1 (en) 1999-07-20 2001-01-26 St Microelectronics Sa Sizing a system has electromagnetic transponder for operation in extreme closeness
US6803744B1 (en) 1999-11-01 2004-10-12 Anthony Sabo Alignment independent and self aligning inductive power transfer system
DE19958265A1 (en) 1999-12-05 2001-06-21 Iq Mobil Electronics Gmbh A wireless power transmission system with increased output voltage
US6650227B1 (en) 1999-12-08 2003-11-18 Hid Corporation Reader for a radio frequency identification system having automatic tuning capability
US6450946B1 (en) * 2000-02-11 2002-09-17 Obtech Medical Ag Food intake restriction with wireless energy transfer
US6569397B1 (en) * 2000-02-15 2003-05-27 Tapesh Yadav Very high purity fine powders and methods to produce such powders
US6561975B1 (en) 2000-04-19 2003-05-13 Medtronic, Inc. Method and apparatus for communicating with medical device systems
JP4140169B2 (en) 2000-04-25 2008-08-27 松下電工株式会社 Contactless power transmission system
JP3830892B2 (en) 2000-06-12 2006-10-11 三菱電機株式会社 Portable radio
JP2001359279A (en) 2000-06-12 2001-12-26 Sony Corp Bridge-type dc-dc converter
DE10029147A1 (en) 2000-06-14 2001-12-20 Ulf Tiemens Installation for supplying toys with electrical energy, preferably for production of light, comprises a sender of electromagnetic waves which is located at a small distance above a play area with the toys
US6452465B1 (en) * 2000-06-27 2002-09-17 M-Squared Filters, Llc High quality-factor tunable resonator
JP4135299B2 (en) 2000-06-27 2008-08-20 松下電工株式会社 Contactless power transmission system
US6563425B2 (en) * 2000-08-11 2003-05-13 Escort Memory Systems RFID passive repeater system and apparatus
GB2370509A (en) 2000-08-29 2002-07-03 Don Edward Casey Subcutaneously implanted photovoltaic power supply
DE20016655U1 (en) * 2000-09-25 2002-03-21 Ic Haus Gmbh System for wireless power and data transmission
JP3851504B2 (en) 2000-11-16 2006-11-29 矢崎総業株式会社 Automobile power supply device for a sliding door
JP2004519310A (en) * 2001-04-11 2004-07-02 ジン−ギュ パーク, Seat cushion seat
US7282889B2 (en) * 2001-04-19 2007-10-16 Onwafer Technologies, Inc. Maintenance unit for a sensor apparatus
JP3629553B2 (en) 2001-05-08 2005-03-16 インターナショナル・ビジネス・マシーンズ・コーポレーションInternational Business Maschines Corporation Power supply system, a computer device, a battery, a method of protecting an abnormal charge, and program
WO2002093248A1 (en) * 2001-05-15 2002-11-21 Massachussets Institute Of Technology Mach-zehnder interferometer using photonic band gap crystals
WO2003036760A1 (en) 2001-10-22 2003-05-01 Sumida Corporation Antenna coil and transmission antenna
WO2003040968A1 (en) * 2001-11-06 2003-05-15 Naoto Morikawa Shape processor and method for representing shape
FR2832272B1 (en) 2001-11-09 2004-09-24 Commissariat Energie Atomique growth passive device of the transmission systems of efficiency radiofrequency
US7180503B2 (en) * 2001-12-04 2007-02-20 Intel Corporation Inductive power source for peripheral devices
JP4478366B2 (en) 2001-12-11 2010-06-09 ソニー株式会社 Non-contact communication system
US6832735B2 (en) * 2002-01-03 2004-12-21 Nanoproducts Corporation Post-processed nanoscale powders and method for such post-processing
US6847190B2 (en) 2002-02-26 2005-01-25 Linvatec Corporation Method and apparatus for charging sterilizable rechargeable batteries
JP3671919B2 (en) 2002-03-05 2005-07-13 日立電線株式会社 Coaxial cable and coaxial multi-conductor cable
US20040093041A1 (en) 2002-03-15 2004-05-13 Macdonald Stuart G. Biothermal power source for implantable devices
WO2003081324A1 (en) 2002-03-18 2003-10-02 Clarendon Photonics, Inc. Optical filter with dynamically controlled lineshape and method of operation
US6683256B2 (en) 2002-03-27 2004-01-27 Ta-San Kao Structure of signal transmission line
JP3719510B2 (en) * 2002-04-08 2005-11-24 アルプス電気株式会社 Vault with a non-contact type charger
US6906495B2 (en) * 2002-05-13 2005-06-14 Splashpower Limited Contact-less power transfer
JP4403285B2 (en) 2002-05-13 2010-01-27 アムウェイ(ヨーロッパ)リミテッドAmway(Europe)Limited Improvement over non-contact power transmission
GB0210886D0 (en) * 2002-05-13 2002-06-19 Zap Wireless Technologies Ltd Improvements relating to contact-less power transfer
US7239110B2 (en) * 2002-05-13 2007-07-03 Splashpower Limited Primary units, methods and systems for contact-less power transfer
DE10221484B4 (en) 2002-05-15 2012-10-11 Hans-Joachim Holm Device for supplying power to a data acquisition and data transmission unit as well as data acquisition and transmission unit
US6844702B2 (en) * 2002-05-16 2005-01-18 Koninklijke Philips Electronics N.V. System, method and apparatus for contact-less battery charging with dynamic control
JP4668610B2 (en) 2002-05-24 2011-04-13 テレフオンアクチーボラゲット エル エム エリクソン(パブル) The method of user authentication for the service of the service provider
US20040026998A1 (en) 2002-07-24 2004-02-12 Henriott Jay M. Low voltage electrified furniture unit
US7147604B1 (en) 2002-08-07 2006-12-12 Cardiomems, Inc. High Q factor sensor
US6856291B2 (en) * 2002-08-15 2005-02-15 University Of Pittsburgh- Of The Commonwealth System Of Higher Education Energy harvesting circuits and associated methods
US6772011B2 (en) 2002-08-20 2004-08-03 Thoratec Corporation Transmission of information from an implanted medical device
US6609023B1 (en) 2002-09-20 2003-08-19 Angel Medical Systems, Inc. System for the detection of cardiac events
US6858970B2 (en) 2002-10-21 2005-02-22 The Boeing Company Multi-frequency piezoelectric energy harvester
JP2004166459A (en) 2002-11-15 2004-06-10 Mitsui Eng & Shipbuild Co Ltd Non-contact feeding device
GB0229141D0 (en) * 2002-12-16 2003-01-15 Splashpower Ltd Improvements relating to contact-less power transfer