Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q1/00—Details of, or arrangements associated with, antennas
  • H01Q1/12—Supports; Mounting means
  • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
  • H01Q1/2208—Supports; Mounting means by structural association with other equipment or articles associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems
  • H01Q1/2225—Supports; Mounting means by structural association with other equipment or articles associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q7/00—Loop 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

Definitions

• the smartcard may comprise a card body (CB) made of plastic or metal or a combination thereof, and a transponder chip module (TCM) comprising a dual interface RFID chip and a module antenna (MA).
• CB card body
• TCM transponder chip module
• a dual interface (DI or DIF) smartcard (or smart card; SC) may generally comprise:
• AM antenna module
• TCM transponder chip module
• BA booster antenna
• the antenna module “AM” may generally comprise a "DI” RFID chip (bare, unpackaged silicon die) or chip module (a die with leadframe, interposer, carrier or the like) - either of which may be referred to as "CM” - mounted to a module tape "MT".
• the RFID chip (CM) may be mounted on a module tape (MT), typically having 6 or 8 contact pads (CP) for interfacing with a contact reader in a contact mode (ISO 7816).
• a module antenna "MA” may be disposed on the module tape MT for implementing a contactless interface, such as ISO 14443 and NFC/ISO 15693.
• Contact pads "CP” may be disposed on the module tape MT for implementing a contact interface, such as ISO 7816.
• the contact pads (CP) may or may not be perforated.
• the module tape MT may comprise a pattern of interconnects (conductive traces and pads) to which the RFID chip CM and contact pads CP may be connected.
• the module antenna MA may be connected, indirectly, via some of the interconnects to the chip CM, or may be directly connected to bond pads BP on the RFID chip CM.
• the module antenna MA may comprise several turns of wire, such as 112 micron diameter insulated wire.
• US 6378774 2002, Toppan
• the module antenna (MA) may comprise a chemically-etched, planar module antenna MA with planar tracks surrounding the chip (CM).
• US 8100337 2012, SPS
• the antenna module “AM” may comprise a module antenna (MA) which may comprise a planar antenna structure (AS) which is etched (chemically etched or laser etched, from a foil on the module tape MT) to have a number of tracks separated by spaces. Generally, with laser etching, the spacing between tracks can be made smaller (such as 25 ⁇ ) than with chemical etching (such as 80 or 100 ⁇ ).
• MA module antenna
• AS planar antenna structure
• the spacing between tracks can be made smaller (such as 25 ⁇ ) than with chemical etching (such as 80 or 100 ⁇ ).
• the module antenna (MA) may comprise multilayered planar antenna structures each connected in a clockwise or anticlockwise direction, or a combination thereof.
• the module antenna (MA) may also be connected to a silicon capacitor in series or parallel to regulate the tuning of the resonant circuit.
• a module antenna (MA) connected to an RFID chip (CM) may be referred to as a "transponder”.
• a transponder is a “passive” transponder which does not have its own power source (e.g., battery), but rather which harvests power from an external reader (interrogator).
• the activation distance of an antenna module (AM) having a chemically-etched module antenna (MA), without a booster antenna (BA) in the card body (CB), may be only a few millimeters.
• the activation distance of an antenna module (AM) having a laser-etched antenna structure (LES), without a booster antenna (BA) in the card body (CB) may be 15 - 20 mm.
• the activation distance of antenna module (AM) with a booster antenna (BA) in the card body (CB) is typically four centimeters to meet ISO and EMV standards.
• the addition of a silicon capacitor connected in parallel or series may enhance performance.
• antenna modules may require a booster antenna (BA) in a card body (CB) to achieve these distances.
• antenna modules (AM) incorporating a laser-etched antenna structure (LES) may be able to operate without a booster antenna (BA) in the card body (CB), and may be referred to as transponder chip modules (TCM).
• TCM transponder chip module
• TCM transponder IC module
• the antenna module AM (or transponder chip module TCM) may be generally rectangular, having four sides, and measuring approximately 8mm x 11mm for a 6 contact module and 11mm x 13mm for an 8 contact module.
• transponder chip module (TCM) may be round, elliptical, or other non-rectangular shape.
• the transponder chip module (TCM) may be powered by RF from an external RFID reader, and may also communicate by RF with the external RFID reader.
• An “activation distance” may refer to a distance at which the transponder chip module TCM may harvest sufficient energy from the RFID reader to commence operation.
• a "read/write distance” may refer to a distance at which the transponder chip module TCM may communicate reliably with the external RFID reader.
• the card body CB - which may be referred to as a substrate, or an inlay substrate - may generally comprise one or more layers of material such as Polyvinyl Chloride (PVC), Polycarbonate (PC), PET-G (Polyethylene Terephtalate Glycol-modified), Copolyester, TeslinTM, synthetic paper, paper and the like.
• PVC Polyvinyl Chloride
• PC Polycarbonate
• PET-G Polyethylene Terephtalate Glycol-modified
• Copolyester TeslinTM
• synthetic paper paper and the like.
• the card body CB may be generally rectangular, measuring approximately 54 mm x 86 mm (refer to ISO/IEC 7810), having a thickness of approximately 300 ⁇ thick when referred to as an inlay substrate or 760 ⁇ when referred to as a smartcard.
• the card body CB is typically significantly (such as 30 times) larger than the antenna module AM.
• the booster antenna BA may generally comprise a relatively large winding which may be referred to as a card antenna CA component (or portion) having a number of turns disposed in a peripheral area of the card body CB, and a relatively small coupler coil (or coupler antenna) CC component (or portion) having a number of turns disposed at a coupling area of the card body CB corresponding to the location of the antenna module AM.
• a card antenna CA component or portion
• coupler antenna CC component or portion
• the card antenna CA and coupler coil CC may comprise wire mounted to (embedded in) the card body CB using an ultrasonic tool comprising a sonotrode and a capillary. See, for example US 6698089 and US 6233818.
• the wire may be non-insulated, insulated, or self- bonding wire, having an exemplary diameter in the range of approximately 50 - 112 ⁇ .
• Metallized smartcards may have a faceplate or layer of metal extending over nearly the entire area of the card (except for an opening for the antenna module (AM)), and some smartcards may be made largely of metal.
• the presence of such a metal layer or mass in the smartcard may tend to attenuate contactless communication (e.g., ISO 14443, ISO 15693) between the smartcard and an external reader.
• the contact pads themselves may also tend to attenuate contactless communication.
• metallized smartcards may often function in a contact mode (e.g., ISO 7816) only.
• Foil composite cards and metal cards may be disclosed in ...
• a conductive "compensation loop" CL may be disposed behind the booster antenna BA, extending around the periphery of the card body CB.
• the compensation loop CL may be an open loop having two free ends, and a gap ("gap") therebetween.
• the compensation loop CL may be made of copper cladding.
• skin depth relates to the "skin effect” which is the tendency of an alternating electric current (AC) to become distributed within a conductor such that the current density is largest near the surface of the conductor.
• a “skin depth” or minimum thickness for conducting current may be defined, for a given material at a given frequency. For example, at 13.56 MHz, the skin depth for copper may be approximately 18 ⁇ (17.7047 ⁇ ). For smartcards, 13.56 MHz is a frequency of interest.
• transparency refers to the ability of electromagnetic radiation to pass through a material.
• a threshold for non-transparency (or the ability to interact with RF) may be a fraction of the skin depth for the metal layer in question at a given frequency of interest.
• the non-transparency threshold for copper at 13.56 MHz may be one-tenth of the skin depth, or approximately 1.7 ⁇ .
• Some other objects may include relaxing performance constraints on the booster antenna (BA) of the smart card (SC), including the possibility of eliminating the booster antenna (BA) altogether.
• the invention is generally directed to smartcard with coupling frame antenna and method of increasing activation distance of a transponder chip module.
• a conductive coupling frame antenna being a closed loop antenna circuit with a continuous metal track or path, having a rectangular geometry with a slit (S) and module opening (MO), disposed surrounding and overlapping the module antenna (MA) in a transponder chip module (TCM) or antenna module (AM).
• the coupling frame antenna may have a track or path width at the module opening equal in dimension to the width of the tracks forming the module antenna in the transponder chip module (TCM) or antenna module (AM).
• the metal track or path can be chemically etched aluminum, copper, a metalized surface or the like. At the periphery of the card body, the width of the metal track or path is no less than the skin depth of the metal at the frequency of interest.
• the metal can be replaced by a conductive medium such as silver paste, conductive ink, or the like requiring a greater track or path width to meet the conditions for proper current conduction.
• the coupling frame antenna (CFA) may resemble a one turn antenna as a closed loop circuit.
• the coupling frame antenna may have multiple turns in a closed circuit design to capture the electromagnetic field, and concentrate a greater surface eddy current density around the area of the slit (S) and module opening (MO), to improve the inductive coupling and ultimately the power delivery to the chip.
• the coupling frame antenna may commence in the center of the card body, extending to the right, forming a conductive path along the perimeter of the card body, forming a loop or module opening at an inner position on the left side of the card body, to surround and overlap a module antenna (MA) of a transponder chip module (TCM) or antenna module (AM), creating a slit by extending the track or path back to the periphery of the card body, and completing the coupling frame antenna structure by returning to the start position within the center of the card body.
• a module antenna MA
• TCM transponder chip module
• AM antenna module
• a switch may be provided to disenable the antenna circuit by connecting its terminals across the slit (S) of the coupling frame antenna (CFA).
• a capacitor may be connected across the slit to boost performance.
• the transponder chip module (TCM) may comprise a laser-etched antenna structure (LES), a chemical-etched antenna structure (CES) and a non-perforated contact pad (CP) arrangement.
• a coupling frame antenna (CFA) may be incorporated onto the module tape (MT) for a transponder chip module (TCM).
• a smartcard may comprise an electrically-conductive track or path, referred to herein as a "coupling frame antenna” (CFA) disposed in the card body (CB) around at least two sides (or 180°) of a transponder chip module (TCM) so as to be in close proximity with the module antenna (MA) in the transponder chip module (TCM).
• the coupling frame antenna (CFA) may at least partially surround the transponder chip module (TCM), such as surrounding two sides (or 180°) or three sides (or 270°) of the transponder chip module (TCM), particularly the antenna structure (AS) of the transponder chip module (TCM).
• the coupling frame (CF) may nearly completely surround the transponder chip module (TCM), such as all four sides (or 360°) thereof, minus a slit (S).
• the slit (S) may be very small, such as 50 ⁇ .
• the module antenna (MA) may comprise an antenna structure (AS) which has been etched from a conductive layer or foil to have a conductor having two ends and arranged in a spiral pattern which has a number (such as 10-14) of turns (which may be referred to as "tracks"), separated by spaces.
• An end portion of an antenna structure (AS) may also comprise of a quarter, half or three quarter turn (fractions of turns).
• a coupling frame antenna (CFA) surrounding all four sides (nearly 360°) of the transponder chip module (TCM) may be provided with a module opening (MO) for accommodating the transponder chip module (TCM), and may be provided with a slit (or slot, or cut-out, or gap) extending from the module opening (MO) to the perimeter of the coupling frame antenna (CFA).
• a switch (SW) may be incorporated into the card body to connect across the slit (S) of the coupling frame antenna (CFA) to short circuit its function of concentrating the distribution of surface eddy currents around the module opening.
• the coupling frame antenna may comprise a conductive layer, a metallized layer, a metal layer or overlapping metal layers, each layer at least partially surrounding the transponder chip module (TCM) and (in aggregate, in the case of two or more conductive layers) covering at least a substantial area of the card body (CB) for coupling with an external contactless reader.
• the coupling frame antenna may comprise one or more continuous tracks or paths of conductive material in the form of a perforated metal mesh or a wireframe metal mesh, or other continuous surface (including embedded ribbon conductor) to avoid electrostatic discharge (ESD) problems.
• a coupling frame antenna (CFA) with a cut-out (module opening MO) to accept the transponder chip module (TCM) may be positioned in or on the card body to partially surround at close proximity to a laser-etched antenna structure (LES) or chemical-etched antenna structure (CES) of the transponder chip module (TCM).
• LES laser-etched antenna structure
• CES chemical-etched antenna structure
• the coupling frame antennas disclosed herein may be formed from tracks or paths of various metals (such as copper, aluminum (aluminium), brass, titanium, tungsten, stainless steel, silver, graphene, silver nanowires, conductive carbon ink), and may be in the form of ribbon cable, or the like, which could be hot stamped into a track or path of the card.
• the transponder chip module may comprise an RFID (radio frequency identification) chip or chip module (either of which may be referred to as "CM”) and an etched (typically planar) antenna structure formed as a flat rectangular spiral having a number (such as 10-14) of conductive tracks separated by spaces.
• the spaces between adjacent tracks can be less than ⁇ , less than 75 ⁇ , less than 50 ⁇ and less than 25 ⁇ .
• the tracks may typically have a width of ⁇ .
• Laser-etching an antenna structure or structures underneath and surrounding a chip (CM) mounted on a module tape (MT) may improve the overall electrical parameters of the antenna.
• a coupling frame antenna at least partially surrounding and overlapping a transponder chip module (TCM) and residing substantially on the same plane as the laser- etched antenna structure (LES) or chemical- etched antenna structure (CES) in a card body, document or tag, and leaving at least one space or gap such as a cut-out, slit or slot in the coupling frame antenna (CFA), may further increase the amplitude of the resonance curve of the transponder chip module (TCM) with minimal frequency shift when interrogated by a reader.
• CFA coupling frame antenna
• the activation distance of a transponder chip module (TCM) with a coupling frame antenna (CFA) may be substantially increased by at least a factor of 1.5, as opposed to the performance of a transponder chip module (TCM) without a coupling frame antenna (CFA).
• Activation distances of at least 2 cm, including up to 3cm and up to 4cm may be achieved using a transponder chip module (TCM) having a laser-etched antenna structure (LES) or chemical-etched antenna structure (CES) in conjunction with a coupling frame antenna (CFA) in (or comprising most of) the card body (CB).
• TCM transponder chip module
• LES laser-etched antenna structure
• CES chemical-etched antenna structure
• a coupling frame antenna may be used in conjunction with a holographic metal foil (refer to as holofoil), if the holofoil is transparent to high frequency electromagnetic waves and does not impair or influence the performance of a transponder chip module.
• the TCM may be implanted in a metal foil card because the thickness of the metal is significantly lower than the skin depth of the metal at a frequency of interest, such as 13.56 MHz, or more generally 10 - 30 MHz.
• the coupling frame antenna may be a continuous one turn conductor being a closed loop circuit (having no start or end) with a resonance frequency in the ultrahigh frequency range such as in the bandwidth of 2-5 GHz.
• the coupling frame antenna (CFA) may broken at some point along its path to facilitate connection of a device such as an LED or capacitor.
• a device may be connected in parallel across part of the CFA where winding(s), or part thereof, run parallel or in sufficient proximity to each other.
• the width of the one turn antenna may be wider around the area where the module antenna is overlapping the conductive track of the coupling frame antenna.
• the surface eddy current may flow along the outer perimeter edge of the coupling frame antenna, while in the area of the slit, slot, gap or contour, the current may flow around the inner perimeter where the module antenna overlaps the coupling frame antenna.
• the area where the transponder resides in a smarcard is prescribed by an ISO standard.
• the invention relates broadly to RFID transponders which are able to transmit data to and receive data from an external reader.
• Such transponders may generally fall into two categories - “active” and “passive”.
• Active transponders have an internal power source, such as a battery.
• Passive transponders are powered by (harvest power from) the external reader. Due to the lack of their own power source, several factors may influence the successful operation of a passive transponder, some of which are addressed herein. For example, the distance at which a passive transponder may be activated (powered up by) and communicate reliably (read/write) with the external reader may be very limited. Consequently, smart cards (SC) comprising passive transponders have typically required booster antennas (BA) in the card body (CB).
• BA booster antennas
• passive RFID transponders comprising (passive) transponder chip modules (TCM) are discussed, and unless otherwise specified, all embodiments are directed to passive RFID transponders and transponder chip modules (TCM).
• Passive RFID transponders and transponder chip modules (TCM) disposed in smart cards (SC) (including metal foil smart cards and plastic metal hybrid smart cards) and capable of operating in a contactless mode without requiring a conventional booster antenna (BA) (being replaced by a coupling frame antenna (CFA) are disclosed herein.
• a conductive coupling frame antenna may have a continuous track or path, may form a complete loop, may be disposed surrounding and closely adjacent a transponder chip module (TCM), and may be substantially coplanar and overlapping with an antenna structure (AS, LES, CES) in the transponder chip module (TCM).
• a coupling frame antenna (CFA) may have multiple tracks or paths as a continuous track or path.
• a coupling frame antenna (CFA) may be formed on one or both sides of an inlay substrate.
• the coupling frame antenna (CFA) may be a closed circuit on one side of the inlay substrate, while the antenna on the opposite side of the substrate may be an open circuit having a start and end position.
• the transponder chip module (TCM) may comprise a laser- etched antenna structure (LES) or chemical-etched antenna structure (CES) and a non- perforated contact pad (CP) arrangement.
• the coupling frame antenna (CFA) may extend over a periphery area of the smartcard.
• the coupling frame antenna (CFA) may commence at the center of the card body, at so-called center of technology (COT), in order to operate in a similar manner as a conventional booster antenna, and meet the test conditions defined by EMV standards.
• COT center of technology
• a smartcard has a card body (CB) and a conductive coupling frame antenna (CFA) extending as a closed loop circuit around a periphery of the card body, and also extending inwardly so that two portions of the coupling frame antenna are closely adjacent each other, with a gap therebetween.
• the gap may extend from a periphery of the card body to a position corresponding with a module antenna (MA) of a transponder chip module (TCM) disposed in the card body, and may function like a slit (S) in a coupling frame (CF).
• a portion of the coupling frame antenna may be arranged to surround an area which is the ISO position of the transponder chip module in the card body.
• a coupling frame antenna (CFA) may be incorporated onto a module tape (MT) for a transponder chip module (TCM).
• a smartcard may comprise a card body (CB), wherein a given area of the card body is designated for receiving a transponder chip module (TCM) having a module antenna (MA); and may be characterized by: a coupling frame antenna (CFA) comprising conductive track routed around a perimeter of the card body, and further routed toward the interior of the card body to the area designated for receiving the transponder chip module, resulting in two portions of the coupling frame antenna (CFA) being closely adjacent one another with a gap (S, 203, 303) therebetween, the gap extending from a peripheral edge of the card body to the area of the card body designated for receiving the transponder chip module (TCM).
• CFA coupling frame antenna
• a portion of the conductive track may surround the (ISO) area designated for receiving the transponder chip module.
• a portion of the conductive track may form a loop around the area of the card body designated for receiving a transponder chip module (TCM).
• TCM transponder chip module
• a transponder chip module may be disposed in the loop, and a portion of the coupling frame antenna may overlap a portion of the module antenna (MA) in the transponder chip module.
• the gap of the coupling frame antenna may overlap a overlap a portion of the module antenna (MA) in the transponder chip module.
• the coupling frame antenna (CFA) may comprise a single-turn, closed-loop circuit.
• the coupling frame antenna may begin in the center of the card body and extend over the peripheral area of the smartcard.
• the conductive track may have a width greater than its skin depth at a frequency of interest.
• the conductive track may comprise multiple tracks.
• the coupling frame antenna may be formed on one side of an inlay substrate.
• a second coupling frame antenna may be formed on another side of the inlay substrate.
• One of the coupling frame antennas may be formed as a closed circuit, and the other of the coupling frame antennas may be formed as an open circuit, having a start and an end position.
• the invention(s) described herein may relate to industrial and commercial industries, such RFID applications, payment smartcards, loyalty cards, gift cards, hotel keycards, identity cards, access control cards, wearable devices the like.
• Radio frequency identification (RFID) enabled smartcards which communicate in contactless mode with a reader or point-of-sale (POS) terminal have been around for over 20 years. These passive devices operating at the 13.56 MHz ISM frequency are energized by the electromagnetic field propagated by a POS terminal. The same RFID technology also applies in national identity cards and electronic passports. More recently, financial cards (prepaid, debit and credit cards) have both a contact and contactless interface, so-called dual interface (DIF) chip cards, with the contactless interface being used for micro-payment transactions.
• DIF smartcard has a transponder chip module implanted and an in-card booster antenna embedded into the card body, with no physical electrical contact between the chip module and the antenna.
• the transponder chip module has a 6 or 8 contact pad array on its obverse side and a miniature antenna (micro-coil) routed around an RFID chip on its reverse side.
• the operation between the transponder chip module and its companion in-card booster antenna is referred to as "inductive coupling".
• High frequency structural simulator (HFSS) models on coupling frames with cut-out/slits and overlapping transponder chip modules provided finite element calculations and measurements.
• 2D inductive magnetic field profiles showed that the field concentration runs along the coupling frame perimeter in addition to the position of the cut-out/slit. Inductance is created due to the flow of the surface eddy currents around the area of the cut-out/slit, coupling in close proximity with the overlapping antenna structure of the transponder chip module.
• This system can be compared with an air coupled transformer, with a transformer ratio close to 55: 1 being achieved.
• the profiles proved that the field was evidently enhanced in magnitude when the transponder chip module was combined with the coupling frame.
• a dominant control parameter of the coupling frame in combination with the transponder chip module was the front-end capacitance of the module's CMOS chip.
• the underlying physical mechanism is reactive coupling between the cut-out/slit and transponder chip module.
• the input capacitance of dual interface semiconductor chips have increased significantly in recent times (from 17 pf to 69 pF, and to more than 100 pF) reducing the need to have a complex booster antenna structure for inductive coupling in a dual interface smartcard.
• a metallic RFID tag comprising of a slit in a metal plate and a window shaped slot to accept a small loop antenna.
• the antenna is designed for a Texas Instrument ultra high frequency (UHF) chip, whose input impedance is about (10.7-j62.8) ⁇ at 925 MHz.
• UHF Texas Instrument ultra high frequency
• the small loop antenna inductively couples the energy to the metal with the corresponding slit and opening. The coupling strength is mainly controlled by the distance between the window slot and the loop antenna.
• US 8608082 [6] (2013-12-17, LeGarrec et al, ⁇ 82) describes a method for amplifying the gain of an antenna in a transponder SIM device using a planar metal layer with a slit surrounding the periphery of the device; the metal layer does not overlap the antenna structure of the transponder, nor does it consider such an overlap as being an enhancing factor: "In conformity with an embodiment of the invention, the element extends around the antenna outside of an area defined by the projection of the antenna along a direction substantially orthogonal to the antenna surface. Thus, the antenna and the ring must not extend facing one another so as not to mask the magnetic field flux through the antenna surface.
• the element extends outside the outer perimeter of the antenna in a plane parallel to that containing the antenna or part of the antenna, or possibly in the same plane. However, when the element extends within the same plane as the antenna or part of the antenna, a minimum spacing is provided between the element and the antenna to ensure electrical isolation.”
• Mukherjee [7] explains how a metal surface in the vicinity of an air coupled reader-transponder system significantly degrades the performance.
• the electromagnetic field generated by the reader induces eddy currents on the surface of the metal, creating a magnetic field in opposition to the original field reducing the magnetic flux, and therefore inductance. Furthermore, reduction of the effective magnetic field reduces the power delivery to the chip.
• the prior art may not consider the importance of the overlap of the coupling frame or coupling frame antenna with the module antenna of the transponder chip module, and more specifically the degree of overlap to achieve a contactless smartcard which is compliant with the EMVCo (Europay MasterCard Visa) contactless specification for payment systems. It is not just a question of transponder activation distance, but having optimum read/write performance with respect to responsiveness, timing, quality factor, load modulation and data communication at off-resonance side-lobe frequencies under different conditions of field intensity and without the presence of read holes or data clipping.
• EMVCo Europay MasterCard Visa
• FIGs The figures may generally be in the form of diagrams. Some elements in the figures may be exaggerated, others may be omitted, for illustrative clarity. Some figures may be in the form of diagrams.
• FIG. 1 is a diagram, in cross-section, of a conventional dual-interface smart card (SC) and readers.
• SC smart card
• FIG. 2 is a diagram, of an exemplary coupling frame antenna with a track width of 3 mm.
• FIG. 3 is a diagram, of an exemplary coupling frame antenna with its start position in the center of the card body.
• FIG. 4 is a diagram, of an exemplary coupling frame antenna with multiple track sections extending inwards toward the centre of the card.
• RFID cards, electronic tags and secure documents in the form of pure contactless cards, dual interface cards, phone tags, electronic passports, national identity cards and electronic driver licenses may be discussed as exemplary of various features and embodiments of the invention(s) disclosed herein. As will be evident, many features and embodiments may be applicable to (readily incorporated in) other forms of smart cards, such as EMV payment cards, metal composite cards, metal hybrid cards, metal foil cards, access control cards, hotel keycards and secure credential documents. As used herein, any one of the terms “transponder”, “tag”, “smart card”, “data carrier”, “wearable device” and the like, may be interpreted to refer to any other of the devices similar thereto which operate under ISO 14443 or similar RFID standard. The following standards are incorporated in their entirety by reference herein:
• ISO/IEC 14443 Identity cards - Contactless integrated circuit cards - Proximity cards
• ISO/IEC 14443 is an international standard that defines proximity cards used for identification, and the transmission protocols for communicating with it.
• ISO/IEC 15693 is an ISO standard for vicinity cards, i.e. cards which can be read from a greater distance as compared to proximity cards.
• ISO/IEC 7816 is an international standard related to electronic identification cards with contacts, especially smart cards.
• EMV standards define the interaction at the physical, electrical, data and application levels between IC cards and IC card processing devices for financial transactions. There are standards based on ISO/IEC 7816 for contact cards, and standards based on ISO/IEC 14443 for contactless cards.
• a typical data carrier described herein may comprise
• TCM transponder chip module
• AS laser-etched antenna structure
• the antenna structure may be laser-etched, or chemically-etched, and may be substantially planar having a number of tracks separated by spaces (ii) a card body (CB) (which may be referred to simply as a "card”), and
• CFA coupling frame antenna
• chip module When “chip module” is referred to herein, it should be taken to include “chip”, and vice versa, unless explicitly otherwise stated.
• transponder chip module (TCM)
• A antigenna module
• TCM transponder chip module
• TCM transponder IC module
• the transponder chip module may comprise non-perforated isolated metal features such as contact pads on the face-up side of the module tape (MT) and a laser-etched antenna structure or structures (LES) on the face-down side of the module tape (MT). Certain components on either side of the module tape (MT) may be chemically etched. An antenna structure incorporated directly on the chip may inductively couple with the laser-etched antenna structure.
• CM complementary metal-oxide-semiconductor
• IC integrated circuit
• RFID chip a chip module
• some figures present examples that are specifically “chip modules” having IC chips (such as a “CM”) mounted and connected to substrates.
• a “chip module” (die and carrier) with a laser-etched antenna structure (LES) and connected thereto may be referred to as a transponder chip module (TCM).
• inlay substrate When “inlay substrate” is referred to herein, it should be taken to include “card body”, and vice versa, as well as any other substrate for a secure document, unless explicitly otherwise stated.
• Component elements such as a switch, capacitor, inductor, resistor, an LED, or anti-shielding material such as ferrite can be included as an integral part of the transponder chip module or the coupling frame antenna.
• DI, DIF dual interface
• Many of the teachings set forth herein may be applicable to pure contactless cards, tags, secure documents (e.g. electronic passports) and the like having only a contactless mode of operation.
• any dimensions set forth herein are approximate, and materials set forth herein are intended to be exemplary. Conventional abbreviations such as “cm” for centimeter”, “mm” for millimeter, “ ⁇ ” for micron, and “nm” for nanometer may be used.
• FIG. 1 illustrates a smart card SC 100 in cross-section, along with a contact reader and a contactless reader.
• An antenna module (AM) or transponder chip module (TCM) 110 may comprise a module tape (MT) 112, an RFID chip (CM) 114 disposed on one side (face-down) of the module tape MT along with a module antenna (MA) 116 and contact pads (CP) 118 disposed on the other (face-up) side of the module tape MT for interfacing with an external contact reader.
• the card body (CB) 120 comprises a substrate which may have a recess (R) 122 extending into one side thereof for receiving the antenna module AM.
• the recess R may be stepped - such as wider at the surface of the card body CB - to accommodate the profile of the antenna module AM.
• the booster antenna BA 130 may comprise turns (or traces) of wire (or other conductor) embedded in (or disposed on) the card body CB, and may comprise a number of components such as (i) a card antenna (CA) component 132 and (ii) a coupler coil (CC) component 134. It may be noted that, as a result of the recess R being stepped, a portion of the card body (CB) may extend under a portion of the antenna module AM, more particularly under the module antenna MA.
• Holographic metal foils may be glued or laminated to both sides of the booster antenna BA inlay (card body CB).
• the holographic metal foils may not significantly attenuate the electromagnetic field, in other words the holographic metal foils may be largely transparent to the RF field.
• the holographic metal foils can be used to mask (visually hide) the presence of the booster antenna BA.
• the holographic metal foils when placed either side (above, below) of the booster antenna BA can generate capacitance which may help improve the communication performance of the smart card with the reader (FIG. 1).
• FIG. 2 is a diagram of an exemplary coupling frame antenna (CFA) with a track width of approximately 3 mm.
• the design shown illustrates a continuous closed loop single track coupling frame antenna (CFA) 202 placed within the perimeter defined by the card body (CB) 201.
• CFA coupling frame antenna
• the outer edges of the coupling frame antenna (CFA) 402 may extend to the periphery of the card body (CB) 201 or be offset from the edge of the smartcard by some distance to aid lamination or other assembly of the smartcard's additional layers.
• the path defined by the coupling frame antenna (CFA) 201 extends inwards towards and around the module opening (MO) 204.
• the length, width and track thickness of the coupling frame antenna (CFA) 202 in the vicinity of the module opening (MO) 204 may be set as to provide an optimum overlap with the module antenna (MA) of the transponder chip module (TCM).
• the shape of the coupling frame antenna as it extends inwardly from the left (as viewed) side of the card body to the module opening area, results in two side-by-side portions of the coupling frame antenna (CFA) being closely adjacent each other, with a gap therebetween. This gap may be comparable to the slit (S) in a conventional coupling frame (CF)
• a "coupling frame” may comprise a metal layer, metal frame, metal plate or any electrically-conductive medium or surface with an electrical discontinuity such as in the form of a slit (S) or a non-conductive stripe extending from an outer edge of the layer to an inner position thereof, the coupling frame (CF) capable of being oriented so that the slit (S) overlaps (crosses-over) the module antenna (MA) of the transponder chip module (TCM), such as on at least one side thereof.
• the slit (S) may be straight, and may have a width and a length. In some embodiments, the slit (S) may extend to an opening (MO) for accepting the transponder chip module.
• Coupling frames of this type typically a layer of metal with an opening for receiving a transponder chip module, and a slit extending from a periphery of the layer to the opening, wherein the slit overlaps at least a portion of the module antenna, may be found in US 9812782, US 9390364, US 9634391, US 9798968, and US 9475086.
• the coupling frame antenna (CFA) of the present invention may comprise a continuous conductive path or a track of wire or foil formed around the transponder chip module (TCM), such as by embedding wire or by etching a conductive path or track in the form of a one turn (or single-loop) antenna.
• the coupling frame may be planar or three dimensional (such as a curved surface).
• the coupling frame for inductive coupling with a reader may couple with either a passive or an active transponder chip module.
• the path (or track) of the single-loop coupling frame antenna (CFA) may generally be around the periphery of the card body, but may extend to an inner position of the card body and double back on itself at selected areas of the card body, leaving a gap or void between the adjacent portions of the track.
• the space (void, gap) between closely-adjacent portions of the single-loop coupling frame may perform the function of a slit (S) in a conventional coupling frame - namely, overlap a portion of a module antenna in the transponder chip module - but it is distinctly different in construction.
• the coupling frame antenna (CFA) may wrap around the position (or module opening MO) for the transponder chip module (TCM).
• the term “slit” will be applied to coupling frames (CF), and the term “space” will be applied to the corresponding feature of coupling frame antennas (CFA).
• the term “slit” may be used to describe the space (void, gap) between closely-adjacent portions of the single-loop coupling frame antenna (CFA).
• the overlap of the slit (or space) of either a coupling frame (CF) or a coupling frame antenna (CFA) with the module antenna (MA) may be less than 100%.
• the width and length of the slit (or space) can significantly affect the resonance frequency of the system and may be used as a tuning mechanism. As the width of slit (or space) changes, there is a resulting change in the overlap of the slit with the antenna.
• the slit (S) represents both a mechanical and an electrical discontinuity in an otherwise continuous (electrically and mechanically) structure.
• the slit is a feature extending from an edge of the coupling frame (CF) to an interior position therof (typically, the module opening for the transponder chip module).
• Most of the coupling frames described hereinbefore may have a "continuous" surface, and may comprise a foil or sheet or layer of metal having a slit (an electrical discontinuity) for overlapping a module antenna and, in some cases having an appropriate opening (MO) for accommodating mounting the transponder chip module.
• Coupling frames may be printed, and may be made up of a wire grid or array (such as wire embedding wire (copper or silver) and making a physical connection through overlapping wires to create a coupling frame.
• the coupling frame could also be a metal mesh.
• a "discontinuous" coupling frame could be made from a solid metal layer, or from embedding wire in a suitable pattern in a substrate, both of which would be arranged to exhibit a slit/discontinuity.
• the coupling frame antenna (CFA) described herein is easily distinguishable from previous coupling frames (CF) in that it does not have a slit extending from an outer edge thereof to an inner position thereof, and is generally a continuous structure. It is within the scope of the invention , however, that the coupling frame antenna (CFA) may be broken (made to be discontinuous) at some point along its length, in which case it may be cosidered to be an "open-loop" antenna rather than a "closed-loop” antenna.
• a closed-loop single- turn continuous-tract antenna with a folded/contour shape resulting in narrow spaces between closeley-adjacent portioins of the track can function as a coupling frame, the space in the contoured antenna serving the purpose of the slit in a coupling frame, both the slit and space preferably overlapping at least a portion of the module antenna in the transponder chip module.
• a benefit of the contoured antenna having a space, rather than a coupling frame having a slit is that the slit in the coupling frame is a mechanical discontinuity that may slightly compromise the mechanical integrity of the card.
• the contoured antenna does not suffer from this disadvantage, because there is no mechanical discontinuity in its single-loop structure.
• the gap (S) 203 as shown extends from the outer perimeter of the coupling frame antenna (CFA) 202 and intersects the module opening (MO) 204.
• a device for example and LED or capacitor, may be connected across the gap (S) 203 or any other part of the coupling frame antenna (CFA) 202 in order to provide an additional function to the CFA 202 or to affect the resonance frequency of the device.
• the coupling frame antenna (CFA) 202 may be broken at some point to permit connection of a device which in turn completes the circuit of the coupling frame antenna and gives an effectively continuous track.
• the coupling frame antenna is a continuous track with no start or end, in short a closed loop circuit having a contour or form which wraps around or surrounds the position for the placement of a transponder chip module, having a module antenna which overlaps the coupling frame antenna on one side, two sides, three sides or on all four sides.
• the gap, slot, cut out, slit or opening does not cause an electrical discontinuity in the coupling frame antenna.
• the transponder chip module inductively couples with the coupling frame antenna through its module antenna harvesting the surface current distribution.
• FIG. 3 is a diagram of an exemplary coupling frame antenna (CFA) with its start position in the center of the card body.
• the coupling frame antenna (CFA) 302 is a continuous loop and thus has no well-defined start or end point it may be stated that the coupling frame antenna (CFA) 302 describes a path that extends inwards towards the center of the card body (CB) 301 from the right hand edge of the card body (CB) 301 as illustrated.
• a gap 303 (compare 203) is formed by two closely-adjacent portions of the CFA at the left (as viewed) portion of the card body (CB), and this gap 303 may function like a slit in a coupling frame (CF).
• Another gap (S) 309 may be formed by two closely-adjacent portions of the CFA at the right (as viewed) portion of the card body (CB).
• the coupling frame antenna (CFA) 302 shown extends around or near the geometric center of the card plane, which is coincident with the axis defined by EMV standards as the center of technology (COT) 305.
• the purpose of the extension of the coupling frame antenna (CFA) towards or around the center of technology (COT) 305 is to provide spatially uniform signal reception and communication with a reader antenna over and beyond the area defined by the card body (CB) 301 in order to meet required ISO and EMV smartcard standards.
• the distance (D) 307 may be any value so as to permit optimum radio frequency signal pickup by the coupling frame antenna (CFA) 302 at all regions of the card body (CB) 301.
• the antenna bend point (AB) 306 may also have varying shape or be omitted in the case where the inwards-extending tracks of the coupling frame antenna (CFA) 302 run parallel to each other; in this instance the distances (D) 307 and (E) 308 may be equal or similar.
• the distance (E) 308 may also be controlled so as to optimize the spatial radio frequency signal pickup characteristics of the coupling frame antenna (CFA) 302.
• these features are distinctly different different than the slits (S) previously described, for example, in US 9798968, US 9475086, US 9812782 and US 9390364, as are formed by the contour (pattern) of the coupling frame antenna (CFA), rather than extending into the body of a coupling frame (CF) from an outer (or inner) edge thereof.
• S slits
• FIG. 4 is a diagram of an exemplary coupling frame antenna (CFA) 401 that features multiple inward-extending tracks, as a variation of the design shown previously in FIG. 3.
• the path defined by the coupling frame antenna (CFA) 401 extends inwards from the right edge of the card body (CB) 401, as shown, to closely loop around the module opening (MO) 404 before extending outwards towards the right edge of the card body (CB) 401.
• the path then runs inwards to closely loop around the module opening (MO) 404 again before extending outwards once more.
• the running of additional sections of the coupling frame antenna (CFA) 402 around the module opening (MO) 404 in this manner may be used to increase electromagnetic coupling to the module antenna (MA) of the transponder chip module (TCM).
• the coupling frame antenna (CFA) 402 forms a series of S- bends or "switchback" loops that enable a significant length of the coupling frame antenna (CFA) to pass through or around the center of technology (COT) 405.
• COT center of technology
• a metal surface or a conductive surface of suitable thickness and dimension acting as a coupling frame can replace (or obviate the need for) a booster antenna (BA) in a dual interface smartcard (SC).
• the coupling frame in a card body (CB), tag, document or the like may operate on the principle of inductive capacitive coupling, concentrating surface eddy currents around the module antenna of a transponder chip module (TCM) which may have a laser-etched antenna structure (LES).
• TCM transponder chip module
• LES laser-etched antenna structure
• a dual interface smart card may comprise:
• TCM transponder chip module
• AS antenna structure
• CB card body
• ML metal layer
• CF open loop coupling frame
• the "open loop" in the metal layer may refer to the opening (MO) in the metal layer to accept the transponder chip module.
• the metal layer itself is a closed circuit (closed loop) with the surface eddy currents running on its outer perimeter edges and then concentrating their distribution at the inner edges of the opening and opening surrounding the module antenna of the transponder chip module.

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• 2018
  • 2018-03-29 EP EP18714520.6A patent/EP3602680B1/de active Active
  • 2018-03-29 ES ES18714520T patent/ES2969889T3/es active Active
  • 2018-03-29 WO PCT/EP2018/058251 patent/WO2018178316A1/en unknown

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