CHIP CARD

• US 20160189024A1
• Filed: 12/18/2015
• Published: 06/30/2016
• Est. Priority Date: 12/29/2014
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: SKACEL, Georg, WEDL, Bernhard, WOERLE, Andreas, RAMPETZREITER, Stephan, BUCHSBAUM, Martin, JONGSMA, Jakob
• Granted Patent: US 9,984,321 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 19/0726 the arrangement including a circuit for tuning the resonance frequency of an antenna on the record carrier
• CPC Class Codes: G06K 19/07794 the record carrier comprising a booster or auxiliary antenna in addition to the antenna connected directly to the integrated circuit

Abstract

According to one embodiment, a chip card is described including a chip, an antenna, a coupling structure configured to transmit energy from the antenna to the chip and a control element configured to control, depending on a field strength of a magnetic field to which the chip card is exposed, at least one of the resonance frequency of the antenna, the quality factor of the antenna and an energy transmission efficiency of the coupling structure.

Claims

1. A chip card, comprising:

a chip;

an antenna;

a coupling structure configured to transmit energy from the antenna to the chip; and

a control element configured to control, depending on a field strength of a magnetic field to which the chip card is exposed, at least one of the resonance frequency of the antenna, the quality factor of the antenna and an energy transmission efficiency of the coupling structure.

2. The chip card of claim 1,

wherein the antenna is galvanically coupled to the chip by the coupling structure.

3. The chip card of claim 1,

wherein the control element is configured to shift the resonance frequency of the antenna away from a predetermined system frequency with increasing field strength of the magnetic field above a threshold of the field strength of the magnetic field.

4. The chip card of claim 1,

wherein the control element is configured to reduce the quality factor of the antenna with increasing field strength of the magnetic field above a threshold of the field strength of the magnetic field.

5. The chip card of claim 1,

wherein the antenna is a booster antenna;

wherein the chip card comprises a chip module antenna circuit comprising the chip and a chip module antenna;

wherein the chip card comprises a booster antenna circuit comprising the booster antenna and a coupling antenna inductively coupled to the chip module antenna, wherein the booster antenna circuit forms a resonant circuit; and

wherein the control element is configured to control at least one of the resonance frequency of the booster antenna circuit, the quality factor of the booster antenna circuit and an inductive coupling between the booster antenna circuit and the chip module antenna circuit depending on a field strength of a magnetic field to which the chip card is exposed.

6. The chip card of claim 5,

wherein the control element is configured to control the mutual inductance of the coupling antenna and the chip module antenna depending on the field strength of the magnetic field.

7. The chip card of claim 6,

wherein the control element is configured to decrease the mutual inductance of the coupling antenna and the chip module antenna with increasing field strength of the magnetic field above a threshold of the field strength of the magnetic field.

8. The chip card of claim 1,

wherein the control element is a variable resistor.

9. The chip card of claim 8,

wherein the variable resistor is a resistor whose resistance depends on the field strength of a magnetic field to which it is exposed.

10. The chip card of claim 9,

wherein the variable resistor comprises a structure showing a giant magnetoresistance effect.

11. The chip card of claim 8,

wherein the variable resistor is arranged in physical contact to the chip to be heated by the chip.

12. The chip card of claim 1,

wherein the control element is a voltage limiting element.

13. The chip card of claim 5,

wherein the control element is a voltage limiting element arranged to shorten at least a part of the coupling antenna or the chip module antenna.

14. The chip card of claim 12,

wherein the voltage limiting element is an element with a non-linear voltage-dependent resistance.

15. The chip card of claim 12,

wherein the voltage limiting element comprises a diode or a varistor.

16. The chip card of claim 5,

wherein the control element is a ferrite core of the coupling antenna.

17. The chip card of claim 5,

wherein the booster antenna circuit further comprises a sense antenna and the control element is a ferrite core of the sense antenna.

18. A chip card, comprising:

a chip;

an antenna;

a coupling structure configured to transmit energy from the antenna to the chip; and

a controller configured to control, depending on a field strength of a magnetic field to which the chip card is exposed, a resonance frequency of the antenna related feature of the antenna.