Universal card interface module for contact free cards

• US 6,173,897 B1
• Filed: 07/27/1998
• Issued: 01/16/2001
• Est. Priority Date: 07/27/1998
• Status: Expired due to Fees

• Current Assignee: PAS Technology A/S
• Original Assignee: PAS Technology A/S
• Inventors: Halpern, John W.
• Primary Examiner(s): LE, THIEN MINH
• Application Number:
  US09/122,672
• Time in Patent Office: 904 Days
• Field of Search: 235/488, 235/486, 235/492, 235/380, 235/375, 235/382.5, 235/382, 340/825.31
• US Class Current: 235/488
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: G06K 19/07788 the antenna being of the capacitive type
• CPC Class Codes: G06K 19/07796 arrangements on the record carrier to allow stacking of a plurality of similar record carriers, e.g. to avoid interference between the non-contact communication of the plurality of record carriers
• CPC Class Codes: G06K 7/10316 using at least one antenna particularly designed for interrogating the wireless record carriers antennas in general H01Q1/22
• CPC Class Codes: G06K 7/10326 the antenna being of the very-near field type, e.g. capacitive
• CPC Class Codes: G06K 7/10336 the antenna being of the near field type, inductive coil

Abstract

Card and Card Reader contain a broadly m-shaped or twin looped antenna consisting of one or more thin conducting layers between plastic laminates wherein the middle branch 18 oscillates in anti-phase with the two outer branches 16 and 17 for proximity coupling applications, whereas all the said three branches oscillate in phase in distant read/write applications.

The prevailingly capacitive positions 15, 13, 14 of the antenna can be utilised for card readers where it is preferred to draw a card through a slot into the interior of a sensor unit where the card may be tested, processed, or if need be, withdrawn. Capacitive transfer may be also useful in cases where the temporary clipping of the card to a piece of equipment will unite its data base to a digital system. The instructive component can best be utilized in informal proximity presentations of the card to a Reader area; and its electromagnetic manifestation can best be used in card identifications a distance of several meters.

In order to avoid in proximity transactions a change of transfer efficiency due to subtle alterations in antenna attitudes relative to each other, or in the spacing from each other, or in other modifications of the environment affecting the radiation resistance of the antennas of the said units, this patent application also describes means for allowing the primary frequency of the oscillator source to fluctuate, and to be self-adapting to said random conditions.

Claims

1. An embedded antenna module for a non-contact integrated circuit (IC) card, comprising:

two coils, at least one of which is formed from electrical conductor strip patterns deposited on a first laminate substrate of said card, and said two coils being connected to an IC chip mounted on said card;

said two coils being driven 180°

out of phase with respect to each other in response to an electromagnetic flux produced by a card reader unit, when said IC card is placed in relatively close proximity to the card reader unit;

wherein said card contains a plurality of laminate substrates, at least two of said plurality of laminate substrates including identical electrical conductor strip patterns deposited thereon.

2. The embedded antenna module of claim 1, wherein said two coils share a common winding.

6. The embedded antenna module of claim 2, wherein said IC chip is connected to said antenna module at a location on said common winding where an average load resistance of said common winding is matched to an impedance of said antenna module at an operating frequency of said IC chip.

7. The embedded antenna module of claim 2, further comprising a common ground plane formed on said laminate substrate, and wherein said two coils have an m shape, with the lower leg portions of said m-shape being widened to form capacitive elements in conjunction with said common ground plane.

3. An embedded antenna module for a non-contact IC card reader unit, comprising:

two coils formed from electrical conductor strip patterns deposited on a first substrate, and said two coils being connected to an IC card data processing electronic circuit through a common feed line;

wherein said two coils share a common winding, and said IC card data processing circuit is connected to said antenna module at a location on said common winding where an average load resistance of said common winding is matched to an impedance of said antenna module at an operating frequency of said IC card data processing circuit;

said two coils being driven 180°

out of phase with respect to each other by said IC card data processing electronic circuit.

4. A non-contact IC card system, comprising:

a portable non-contact IC card data carrier having an antenna module tuned to a first resonant frequency and a card reader unit for reading data from said IC card and for writing data to said IC card and having an antenna module tuned to a second resonant frequency;

said card reader unit producing a carrier wave for contactless communication with said IC card data carrier, said carrier wave having a frequency which produces a maximum bandpass response characteristic in the antenna module of the IC card data carrier when said data carrier and said card reader unit are separated by a predefined optimal distance.

8. The non-contact IC card system of claim 4, wherein said antenna modules each have portions which are primarily inductive and portions which are primarily capacitive, whereby bidirectional data transfer between the data carrier and the card reader unit can be carried out utilizing either an electromagnetic field derived from said inductive portions, or an electrostatic field derived from said capacitive portions of said antenna modules.

9. The non-contact IC card system of claim 8, wherein said embedded antenna modules are further adapted to send and receive data signals by electromagnetic radiation, through development of an in-phase resonance in response to homogeneous field changes passing through or alongside said embedded antenna modules.

5. A dual loop antenna system comprising two antenna loops and an oscillator drive circuit coupled to said two antenna loops, said system being capable of electromagnetically oscillating in at least two modes, one of said modes wherein said loops oscillate in phase opposition to each other, and the other of said modes in which said loops oscillate in phase unison, by virtue of the configuration of the two antenna loops, the mode of oscillation of said system being determined by the oscillating frequency, which is in turn dependent upon the coupling conditions of the antenna systems.

10. An energy transfer system comprising a non-contact IC data carrier card and a card reader unit, wherein said data carrier card and said card reader unit each include an antenna system according to claim 5.

11. The energy transfer system of claim 10, wherein each of the antenna systems of said data carrier card and said card reader unit comprise two coils formed from electrical conductor strip patterns deposited on a first laminate substrate of said card, and said two coils being connected to an IC chip mounted on said card, said two coils corresponding to the two antenna loops;

the two coils of the card being driven 180°

out of phase with respect to each other in response to an electromagnetic flux produced by a card reader unit, when said IC card is placed in relatively close proximity to the card reader unit, and the two coils of the cards being driven in phase unison with each other when said IC card is placed in relatively farther proximity to the card reader unit.

12. The energy transfer system of claim 11, wherein said two coils share a common winding.

13. The energy transfer system of claim 11, wherein said card contains a plurality of laminate substrates with antenna conductors deposited thereon, at least two of said plurality of laminate substrates including identical electrical conductor strip patterns deposited thereon, with other substrates having conductor strip patterns being different to obtain optimal bandpass effects.