WO2012103222A2 - Adaptation d'impédance - Google Patents

Adaptation d'impédance Download PDF

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Publication number
WO2012103222A2
WO2012103222A2 PCT/US2012/022554 US2012022554W WO2012103222A2 WO 2012103222 A2 WO2012103222 A2 WO 2012103222A2 US 2012022554 W US2012022554 W US 2012022554W WO 2012103222 A2 WO2012103222 A2 WO 2012103222A2
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WO
WIPO (PCT)
Prior art keywords
antenna
reactive components
impedance
values
matching circuit
Prior art date
Application number
PCT/US2012/022554
Other languages
English (en)
Other versions
WO2012103222A3 (fr
Inventor
Finn HAUSAGER
Original Assignee
Molex Incorporated
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Molex Incorporated filed Critical Molex Incorporated
Publication of WO2012103222A2 publication Critical patent/WO2012103222A2/fr
Publication of WO2012103222A3 publication Critical patent/WO2012103222A3/fr

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Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/38—Impedance-matching networks
    • H03H7/40—Automatic matching of load impedance to source impedance
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/02—Transmitters
    • H04B1/04—Circuits
    • H04B1/0458—Arrangements for matching and coupling between power amplifier and antenna or between amplifying stages

Definitions

  • This invention relates generally to the field of transmission line impedance matching and more specifically to adaptive impedance matching.
  • Loop antennas such as Near Field Communication (NFC) antennas typically couple portable electronic devices and/or terminals.
  • Fixed tuning of loop antennas, including those used in NFC devices, causes an impedance mismatch that results in power reflections for the NFC transmitter at close range. The resulting reflections, in turn, are likely to cause noise in the receiver, as well as errors in transmission due to hard loading of the transmitter. Detuning caused by nearby metal objects further reduces the transmission range. Additionally, antenna tolerances can cause variation in performance. Similar impedance matching issues exist with respect to inductive coupling for power transmission, such as via a power pad device. Thus, fixed impedance tuning methods are not effective in overcoming impedance mismatching due to nearby metal object detuning, tolerance variation, and other variable factors.
  • antenna matching circuits employ a plurality of dynamically tunable reactive components and a voltage feedback circuit for adaptively matching impedance at a terminal connected to an antenna, such as a Near Field Communication (NFC) loop antenna in a mobile device.
  • NFC Near Field Communication
  • the matching circuits described herein rely on voltage feedback and use a split capacitor tuning network for adaptively matching impedance variations of narrow band inductive antennas.
  • split inductor tuning networks are used for adaptive impedance matching of narrow band capacitive antennas.
  • the matching circuit topologies and associated methods described herein may be used for dynamically matching impedance of numerous electrical components associated with inductive or capacitive coupling, including, but not limited to, antennas (including mobile phone antennas subject to impedance mismatch due to user and/or environment interaction), inductive power pads, Radio Frequency Identification (RFID) transducers (such as door key readers), FM transmitters (for instance those connecting portable players to a vehicle radio), and the like.
  • RFID Radio Frequency Identification
  • a system for matching an impedance at a terminal comprises a signal generator, a matching circuit connected to the signal generator, and a feedback circuit.
  • the matching circuit includes at least one variable reactance element for dynamically adjusting values of a plurality of reactive components, the at least one variable reactance element configured to: (a) perform a first adjustment of a value of one of the reactive components so as to one of minimize and maximize a feedback voltage at least approximately at resonance, and (b) perform a second adjustment of values of multiple reactive components while maintaining a predetermined relationship among the multiple reactive components as a constant so as to match the impedance.
  • the feedback circuit is connected to the matching circuit and is configured for varying the feedback voltage.
  • a matching circuit for matching an impedance at a terminal.
  • the matching circuit comprises at least one variable reactance element for dynamically adjusting values of a plurality of reactive components, the at least one variable reactance element configured to: (a) perform a first adjustment of a value of one of the reactive components so as to one of minimize and maximize a feedback voltage at least approximately at resonance, and (b) perform a second adjustment of values of multiple reactive components while maintaining a predetermined relationship among the multiple reactive components as a constant so as to match the impedance.
  • a method of matching an impedance at a terminal by adaptively adjusting values of a plurality of reactive components of a matching circuit comprises performing a first adjustment of a value of one of the reactive components so as to one of minimize and maximize a feedback voltage at least approximately at resonance, and performing a second adjustment of values of multiple reactive components while maintaining a predetermined relationship among the multiple reactive components as a constant so as to match the impedance.
  • Figures 1A is schematic diagram illustrating circuit topology for adaptively matching impedance of an inductive load , in accordance with an embodiment of the invention
  • Figure IB is a schematic diagram illustrating a Smith chart reflecting an adaptive tuning step performed via the circuit topology of Figure 1A, in accordance with an embodiment of the invention
  • Figure 1C is a schematic diagram illustrating a scattering plot corresponding to the Smith chart of Figure IB, in accordance with an embodiment of the invention
  • Figure ID is a schematic diagram illustrating a Smith chart reflecting an additional adaptive tuning step performed via the circuit topology of Figure 1 A, in accordance with an embodiment of the invention
  • Figure IE is is a schematic diagram illustrating a scattering plot corresponding to the Smith chart of Figure ID, in accordance with an embodiment of the invention.
  • Figures 2A is a schematic diagram illustrating another circuit topology for adaptively matching impedance of an inductive load, in accordance with an embodiment of the invention
  • Figure 2B is a schematic diagram illustrating a Smith chart reflecting an adaptive tuning step performed via the circuit topology of Figure 2A, in accordance with an embodiment of the invention
  • Figure 2C is a schematic diagram illustrating a scattering plot corresponding to the Smith chart of Figure 2B, in accordance with an embodiment of the invention.
  • Figure 2D is a schematic diagram illustrating a Smith chart reflecting an additional adaptive tuning step performed via the circuit topology of Figure 2A, in accordance with an embodiment of the invention
  • Figure 2E is is a schematic diagram illustrating a scattering plot corresponding to the
  • Figures 3A is a schematic diagram illustrating another circuit topology for adaptively matching impedance of an inductive load, in accordance with an embodiment of the invention.
  • Figure 3B is a schematic diagram illustrating a Smith chart associated with the circuit topology of Figure 3A, in accordance with an embodiment of the invention.
  • Figure 3C is a schematic diagram illustrating another Smith chart associated with the circuit topology of Figure 3A, in accordance with an embodiment of the invention.
  • Figure 3D is a schematic diagram illustrating a scattering plot associated with a state of the tuning circuit of Figure 3A, in accordance with an embodiment of the invention.
  • Figure 3E is a schematic diagram illustrating a Smith chart associated with the circuit topology of Figure 3A, in accordance with an embodiment of the invention.
  • Figure 3F is a schematic diagram illustrating another Smith chart associated with the circuit topology of Figure 3A, in accordance with an embodiment of the invention.
  • Figure 3D is a schematic diagram illustrating a scattering plot associated with the tuning circuit of Figure 3A, in accordance with an embodiment of the invention;
  • Figures 4A is a schematic diagram illustrating another circuit topology for adaptively matching impedance of an inductive load, in accordance with an embodiment of the invention.
  • Figures 4B, 4C are schematic diagrams illustrating Smith charts associated with respective states of the circuit of Figure 4A, in accordance with an embodiment of the invention
  • Figure 4D is a schematic diagram illustrating a scattering parameter plot associated with Figure 4C, in accordance with an embodiment of the invention.
  • Figures 4E, 4F are schematic diagrams illustrating Smith charts associated with respective states of the circuit of Figure 4A, in accordance with an embodiment of the invention.
  • Figure 4G is a schematic diagram illustrating a scattering parameter plot associated with Figure 4F, in accordance with an embodiment of the invention.
  • Figures 5A and 5B are schematic diagrams illustrating a further embodiment of a circuit topology for adaptively matching impedance at a terminal connected to a non-50 Ohm source;
  • Figures 5C is a schematic diagram illustrating a Smith chart associated with a state of the circuit topology of Figure 5B, in accordance with an embodiment of the invention.
  • Figure 5D is a schematic diagram illustrating a scattering parameter plot associated with a state of the circuit topology of Figure 5B, in accordance with an embodiment of the invention.
  • Figure 5E is a schematic diagram illustrating a tuning step associated with the circuit topology of Figure 5B, in accordance with an embodiment of the invention.
  • Figure 5F is a schematic diagram illustrating various tuning values for a reactance element of Figure 5E, in accordance with an embodiment of the invention.
  • Figure 5G is a schematic diagram illustrating a scattering parameter plot associated with the tuning step of Figure 5F, in accordance with an embodiment of the invention.
  • Figure 5H is a schematic diagram illustrating another tuning step associated with the circuit topology of Figure 5B, in accordance with an embodiment of the invention.
  • Figure 51 is a schematic diagram illustrating various tuning values for the reactance elemenst of Figure 5H, in accordance with an embodiment of the invention.
  • Figure 5J is a schematic diagram illustrating a scattering parameter plot associated with the tuning step of Figure 5H, in accordance with an embodiment of the invention.
  • Figures 6A is schematic diagram illustrating circuit topology for adaptively matching impedance of a capacitive load , in accordance with an embodiment of the invention
  • Figure 6B is a schematic diagram illustrating a Smith chart reflecting an adaptive tuning step performed via the circuit topology of Figure 6A, in accordance with an embodiment of the invention
  • Figure 6C is a schematic diagram illustrating a scattering plot corresponding to the Smith chart of Figure 6B, in accordance with an embodiment of the invention.
  • Figure 6D is a schematic diagram illustrating a Smith chart reflecting an additional adaptive tuning step performed via the circuit topology of Figure 6A, in accordance with an embodiment of the invention.
  • Figure 6E is a schematic diagram illustrating a scattering plot corresponding to the Smith chart of Figure 6D, in accordance with an embodiment of the invention.
  • Figure 7 is a schematic diagram illustrating a general system component layout of the embodiments of the invention.
  • Figure 8 is a flow chart illustrating a method of adaptive impedance tuning in accordance with the embodiments of the invention.
  • antenna matching circuits are provided that employ a plurality of dynamically tunable reactive components and a voltage feedback circuit for adaptively matching impedance at a terminal connected to an antenna, such as a Near Field Communication (NFC) loop antenna in a mobile device.
  • NFC Near Field Communication
  • the matching circuits described herein rely on voltage feedback and use a split capacitor tuning network for adaptively matching impedance variations of narrow band inductive antennas.
  • split inductor tuning networks are used for adaptive impedance matching of narrow band capacitive antennas.
  • the matching circuit topologies and associated methods described herein may likewise be used for dynamically matching impedance of various other electrical elements associated with inductive or capacitive coupling, including, but not limited to antennas (including mobile phone antennas subject to impedance mismatch due to user and/or environment interaction), inductive power pads, Radio Frequency Identification (RFID) transducers (such as door key readers), FM transmitters (for instance those connecting portable players to a vehicle radio), and the like.
  • RFID Radio Frequency Identification
  • a predetermined threshold of the feedback voltage Vfb triggers activation of the embodiments of the matching algorithms described below.
  • the variable reactance elements return to predefined initial values.
  • the inductive element is an inductive loop antenna, such as an NFC loop antenna used in a mobile device, such as a mobile phone, a smart phone, a tablet, a laptop computer, or the like.
  • the antenna is a main RF antenna coupling a mobile device with a base station, or a Radio Frequency Identification (RFID) device antenna.
  • the inductive element forms part of an inductively coupled pay terminal, an electronic door key, an inductively coupled power supply, or another device implementing inductive coupling.
  • the circuit topology 100 includes a signal generator 102 connected to a feedback circuit 104.
  • the signal generator 102 includes input impedance R0, such as 50 Ohms (e.g., representing a 50 Ohm input impedance of a mobile device transmitter).
  • One terminal of the signal generator 102 is connected to a first terminal of a resistor 106 of a high impedance feedback circuit 104.
  • the resistor 106 has a value R4, for example 9950 Ohms.
  • the second terminal of the signal generator 102 is connected to ground 108.
  • the second terminal of the resistor 106 is connected to an amplifier 109, which in turn is connected to a second 50 Ohm variable signal source 110.
  • the matching circuit 112 includes adaptively variable capacitors 114, 116 having respective tunable values CI and C2.
  • the variable capacitors 114, 116 are implemented via at least one variable reactance element 118, such as a digital or an analog Microelectromechanical (or Microelectronic) System (MEMS) device, an electronic varactor, a digitally tunable capacitor circuit, a switched capacitor array, or the like.
  • MEMS Microelectromechanical
  • each of the adaptively tunable capacitors CI and C2 is implemented via a dedicated variable reactance element 118.
  • a single variable reactance element 118 is configured as an adaptively tunable capacitor network CI, C2, where CI and C2 share a pool of switchable reactive elements.
  • CI capacitor bank
  • a plurality of reactive elements is configured in series and individually shorted to increase the capacitance as needed, for example.
  • a multi throw switch selects the capacitor split.
  • each reactive element in the bank is digitally controlled by a processor of a microcontroller executing computer readable instructions stored in memory and comprising an algorithm configured to select a switch configuration based on a feedback signal.
  • the feedback signal triggers different modes like standby, start tuning to resonance, and go to an impedance tune (split).
  • the tuning is implemented via voltage controlled dielectric material for capacitors (BST) (or a ferromagnetic tuned inductor with a movable ferrite core, in case of inductive tuning described below in connection with matching capacitive loads), mechanically tuned capacitor with moving conductive plates or dielectric, for example by using a step motor actuator.
  • BST voltage controlled dielectric material for capacitors
  • MOSFET MOSFET
  • PIN diode switch may be employed.
  • the first terminal of the variable capacitor 114 is connected to the first terminal of resistor 106 of the feedback circuit 104, while the second terminal of the variable capacitor 114 is connected to the first terminal of the variable capacitor 116, which is further connected to ground.
  • the inductive antenna 120 is connected across the terminals of the variable capacitor 116 of the matching circuit 118.
  • the inductive antenna 120 is represented by an inductor 122, having a value LI, and a resistor 124 having a value Rl (e.g., 50 Ohms), which represents radiation and thermal losses.
  • An embodiment of a tuning algorithm initially involves achieving resonance by minimizing the absolute value of the feedback voltage by way of tuning the value CI of the variable capacitor 114. Once resonance is achieved, both values CI and C2 of variable capacitors 114, 116 are tuned to bring the absolute value of the feedback voltage Vfb to 1 ⁇ 2 of the absolute value of the generator voltage Vgen (a known value), while keeping the sum of values CI + C2 as a constant.
  • an algorithm controlled tuning is implemented via a micro controller with analog input to an analog-to-digital converter (ADC) for the feedback voltage.
  • ADC analog-to-digital converter
  • the microcontroller includes one or more digital output pins for controlling the reactance element switches either in a serial or parallel configuration.
  • varactor as tunable capacitor, the is converted back into the analog domain either controlling an external digital-to-analog (DAC) or using an embedded DAC.
  • DAC digital-to-analog
  • Step one of the adaptive tuning process entails adjusting the value of CI until IVfbl at port 2 of the feedback circuit 104 is minimized, which occurs at resonance where the antenna coil reactance is eliminated by the capacitance of CI + C2, as illustrated by the Smith chart of Figure IB and a corresponding scattering parameter graph of Figure 1C.
  • Sl l is nearly real (FIG. IB) and Vfb is minimized (FIG. 1C) at the desired frequency, which is 13.56 MHz in this example.
  • Figures IB and 1C show that changing CI by 2 pF achieves resonance, however the impedance match is not yet perfect.
  • the adjustment is performed by using different Cdelta values until IVfbl or IS21I in Figure IE hits 1, which indicates a perfect match.
  • the first step entails using CI to create resonance by minimizing the voltage Vfb across the generator terminals as follows:
  • the second matching step entails changing both CI and C2 simultaneously in a way that maintains resonance. Resonance occurs if:
  • FIG. 2A another embodiment of a circuit topology for adaptively matching impedance at a terminal connected to an inductive element, such as an antenna, is shown.
  • the circuit topology 200 is similar to that described with respect to Figure 1A above with the exception that the first terminal of resistor 106 of the high impedance feedback circuit 104' is connected to the first terminal of the variable capacitor 116, which further connects to ground 108.
  • the inductive antenna 120 is connected between the first terminal of resistor 106 and ground 108.
  • the feedback voltage Vfb associated with this circuit topology is across the parallel capacitor C2.
  • the tuning algorithm is generally performed in two steps. First, resonance is achieved by maximizing voltage feedback by tuning value CI of the variable capacitor 114. Tuning CI eliminates the reactive element seen from generator and thus maximizes current drawn from generator. Then voltage across the antenna terminal is maximized. Thus, the second step generally involves again maximizing voltage feedback by tuning the values of both CI and C2 while keeping CI + C2 constant. Therefore, no phase information is required to adaptively match the antenna 120.
  • the generator 102 has an impedance of 50 Ohms.
  • Step one of this embodiment of the tuning process entails adaptively adjusting the value of CI until IVfbl at port 2 of the feedback circuit 104' is maximized, which occurs at resonance where the antenna coil reactance is eliminated by the capacitance of CI + C2, as illustrated by the Smith chart of Figure 2B and a corresponding scattering parameter graph of Figure 2C.
  • Sl l is nearly real (FIG. 2B) and Vfb is maximized (FIG. 2C).
  • Figures 2B and 2C show that changing CI by 2 pF achieves resonance, however the impedance match is not yet perfect.
  • the adjustment is performed by using different Cdelta values until IVfbl or IS21I in Figure 2E is maximized, which indicates a perfect match.
  • the second matching step entails changing both CI and C2 simultaneously, while maintaining resonance.
  • Vfb is minimized or maximized.
  • the circuit topology 300 includes a signal generator 302 connected to a high impedance envelope feedback circuit 304.
  • An embodiment of the signal generator 302 has input impedance R0, such as 50 Ohms.
  • One terminal of the signal generator 302 is connected to a first terminal of a resistor 306 of the feedback circuit 304.
  • An embodiment of the resistor 306 has a value R4, for example 9950 Ohms.
  • the second terminal of the signal generator 302 is connected to ground 308.
  • the second terminal of the resistor 306 is connected to an amplifier 309, which in turn is connected to a second 50 Ohm variable signal source 310.
  • the matching circuit 312 includes adaptively variable capacitors 314, 316 having respective tunable values C3 and C4.
  • the variable capacitors 314, 316 are implemented via at least one variable reactance element 318, such as a digital or an analog Microelectromechanical (or Microelectronic) System (MEMS) device, an electronic varactor, a digitally tunable capacitor circuit, a switched capacitor array, or the like.
  • MEMS Microelectromechanical
  • the first terminal of the variable capacitor 316 is connected to the first terminal of resistor 306 of the feedback circuit 304, while the second terminal of the variable capacitor 316 is connected to ground 308.
  • the first terminal of the variable capacitor 316 is also connected to the first terminal of the variable capacitor 314.
  • the inductive antenna 120 is connected between the second terminal of the variable capacitor 314 and ground 308.
  • the inductive antenna 320 is represented by an inductor 322, having a value L2, and a resistor 324, having a value R2 (e.g., 50 Ohms), which represents radiation and thermal losses.
  • the tuning results in offsetting C4 by 30 percent and adding 20 pF to C3.
  • value of C4 is adjusted until IVfbl at port 4 (S42) of the feedback circuit 304 is maximized which occurs very close to resonance where the antenna coil reactance is eliminated by the serial capacitance:
  • Figure 3B illustrates a Smith chart of an initial match
  • Figures 3C and 3D illustrate the effect of reducing C4 by 110 pF, which occurs very close to resonance, and maximizing Vfb.
  • both C3 and C4 are adjusted while maintaining the relation
  • Figure 3E depicts a Smith chart prior to this step.
  • Figures 3F and 3G respectively, show a Smith chart and a scattering parameters plot pursuant to this step when C3 is reduced by 20 pF and C4 is adjusted while maintaining resonance.
  • FIG. 4A another embodiment of a circuit topology for adaptively matching impedance at a terminal connected to an inductive element, such as an antenna, is shown.
  • the circuit topology 400 is similar to that described with respect to Figure 3A above with the exception that the first terminal of resistor 306 of the high impedance feedback circuit 304' is connected to the second terminal of the variable capacitor 316.
  • initial values of C3 and C4 are based on the following formulas:
  • FIG. 5A-5J an embodiment of a circuit topology for adaptively matching impedance at a terminal connected to an inductive antenna using a non-50 Ohm generator is shown.
  • a 50 Ohm load corresponds to a Vfb of 0.236 Vp.
  • FIG. 6A an embodiment of a circuit topology for adaptively matching impedance at a terminal connected to a capacitive element, such as a capacitive antenna, is shown.
  • a capacitive antenna is modeled as a series resistor Ra, representing radiation and loss, and a capacitor Ca, representing a reactance.
  • the matching circuit comprises two variable inductors.
  • a tunable inductor or a positive reactive impedance is achieved using an inductor element.
  • the reactance is increased (or if a conductive surface is brought closer, e.g., mechanically, to an inductor, the reactance is decreased due to an increase in parasitic capacitance).
  • a parallel tunable capacitor may be added to a large inductor, in which case the parasitic capacitance from the capacitor can then be tuned to bring the effective inductance down.
  • the tunable inductors are in series.
  • a tunable capacitor connected through a quarter wave transmission line may be employed so as to act as a positive reactive element such as an inductor.
  • the impedance seen by the generator circuit is:
  • parallel inductor L2 is iteratively adjusted to obtain resonance and then the impedance is tuned while keeping the above relation intact - adjusting both LI and L2 by iteratively adding dL to LI and subtracting dL from L2, thereby maintaining resonance.
  • the process is controlled by using a feedback from the antenna terminal and maximizing the feedback amplitude.
  • First, by bringing circuit in resonance using L2 and then matching the impedance and keeping resonance by adjusting both LI and L2 simultaneously and keeping the LI + L2 constant. During both tuning steps, the feedback amplitude is maximized.
  • the system 700 includes a source/generator 702, a load 706, as well as the matching/feedback circuit 704 connecting the generator to the load and operating in accordance with the embodiments of the adaptively tunable circuit topologies and associated tuning algorithms described above.
  • FIG. 8 is a flow chart illustrating a method of adaptive impedance tuning in accordance with the embodiments of the invention.
  • a first adjustment of a value of one of the reactive components is performed in order to either minimize or maximize a feedback voltage in accordance with the corresponding embodiments of the foregoing circuit topologies described above.
  • the adjustment continues until the circuit is at least approximately at resonance. If so, in step 802, a second adjustment of values of multiple reactive components is made while maintaining a predetermined relationship among the multiple reactive components as a constant so as to match the impedance, as described in detail above.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Details Of Aerials (AREA)
  • Networks Using Active Elements (AREA)
  • Input Circuits Of Receivers And Coupling Of Receivers And Audio Equipment (AREA)
  • Transmitters (AREA)

Abstract

Un circuit d'adaptation permet d'effectuer une impédance au niveau d'une borne. Le circuit d'adaptation comprend au moins un élément à réactance variable en vue de régler de manière dynamique des valeurs d'une pluralité de composants réactifs. Le dit au moins un élément à réactance variable est conçu pour : (a) effectuer un premier réglage d'une valeur de l'un des composants réactifs de façon à minimiser et maximiser sur celui-ci une tension de réaction au moins approximativement à une résonance, et (b) effectuer un second réglage des valeurs de plusieurs composants réactifs tout en maintenant une relation prédéfinie parmi ces composants réactifs sous forme d'une constante de manière à adapter l'impédance.
PCT/US2012/022554 2011-01-27 2012-01-25 Adaptation d'impédance WO2012103222A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US201161436768P 2011-01-27 2011-01-27
US61/436,768 2011-01-27

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WO2012103222A2 true WO2012103222A2 (fr) 2012-08-02
WO2012103222A3 WO2012103222A3 (fr) 2012-09-20

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3010148A1 (fr) 2014-10-16 2016-04-20 Nxp B.V. Réglage d'impédance automatique

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070210899A1 (en) * 2005-01-31 2007-09-13 Akira Kato Mobile Radio Appartus Capable of Adaptive Impedace Matching
US20080122553A1 (en) * 2006-11-08 2008-05-29 Mckinzie William E Adaptive impedance matching module
US20100073103A1 (en) * 2008-09-24 2010-03-25 Spears John H Methods for tuning an adaptive impedance matching network with a look-up table

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070210899A1 (en) * 2005-01-31 2007-09-13 Akira Kato Mobile Radio Appartus Capable of Adaptive Impedace Matching
US20080122553A1 (en) * 2006-11-08 2008-05-29 Mckinzie William E Adaptive impedance matching module
US20100073103A1 (en) * 2008-09-24 2010-03-25 Spears John H Methods for tuning an adaptive impedance matching network with a look-up table

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3010148A1 (fr) 2014-10-16 2016-04-20 Nxp B.V. Réglage d'impédance automatique

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WO2012103222A3 (fr) 2012-09-20
TW201238243A (en) 2012-09-16

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