Smart card with switchable matching antenna
View Patent ↗A smart card having a multi-layer substrate; a transponder module disposed in a first layer of the multi-layer substrate; a first antenna disposed in the first layer of the multi-layer substrate; and a second antenna disposed in a second layer of the multi-layer substrate. A switch and a capacitor in series with the second antenna. The first antenna may be tuned to a different frequency than the second antenna. An RFID chip and antenna in a mold mass disposed in a recess in the first layer of a substrate, behind a hologram disposed on the first layer of the substrate. The switch for the second antenna disposed under the RFID chip. A layer of ferrite material disposed between the hologram and the RFID chip. LEDs disposed behind the hologram.
1. Smart card comprising:
a multi-layer substrate;
a transponder module comprising an RFID chip disposed in a first layer of the multi-layer substrate;
a first antenna disposed in the first layer of the multi-layer substrate and connected to the transponder module; and
a second antenna which is a coupling antenna disposed in a second layer of the multi-layer substrate which is underlying the first layer so that the second antenna is inductively coupled with the first antenna;
wherein the first and second antennas are not connected with one another, but rather are inductively coupled with one another; and
wherein the first antenna is tuned to a first frequency which is relatively far from a desired operating frequency for the RFID chip, and the second antenna is tuned to a frequency which is relatively close to the desired operating frequency.
2. The smart card of claim 1 , further comprising:
a switch disposed in the second layer of the multi-layer substrate, for selectively connecting or disconnecting ends of the second antenna.
3. The smart card of claim 2 , further comprising:
a capacitor disposed in the second layer of the multi-layer substrate, in series with an end of the second antenna.
4. The smart card of claim 2 , wherein:
the switch is selected from the group consisting of a toggle switch, a slide switch, a QTC switch, a piezo film switch and a touch sensor switch.
5. The smart card of claim 1 , wherein:
the first antenna is tuned to approximately 50 MHz, and the second antenna is tuned to approximately 14.5 MHz; and
the desired operating frequency is approximately 13.56 MHz.
6. The smart card of claim 1 , wherein:
the first antenna comprises 1 turn of wire, and the second antenna comprises several turns of wire.
7. The smart card of claim 1 , wherein:
the first antenna has a relatively low Q factor, and the second antenna has a relatively high Q factor.
8. The smart card of claim 1 , wherein:
the first antenna has a relatively low inductivity, and the second antenna has a relatively high inductivity.
9. The smart card of claim 1 , wherein:
the RFID chip is disposed in a recess in the first layer of the substrate.
10. The smart card of claim 1 , wherein:
the RFID chip is disposed on a carrier.
11. The smart card of claim 1 , wherein:
the first antenna is incorporated on the RFID chip.
12. The smart card of claim 1 , wherein:
the chip is disposed in a mold mass.
13. The smart card of claim 1 , further comprising:
a hologram disposed on the first layer of the substrate.
14. The smart card of claim 13 , further comprising:
a layer of ferrite material disposed between the hologram and the RFID chip.
15. The smart card of claim 13 , further comprising:
LEDs disposed behind the hologram.
16. The smart card of claim 1 , further comprising:
a switch for switching the second antenna on and off, to control unauthorized access to the smart card;
wherein the switch is disposed under the RFID chip.