Sideband generating NFC apparatus to mimic load modulation
An RFID card includes a smartcard controller that receives power from a host device. The RFID card also includes a small inductive device capable of inductive coupling with an RFID reader. The small inductive device is small enough to fit in the form factor of a memory card or SIM card. Enhancement circuits enhance the usable read and write distance of the RFID card.
1. An apparatus comprising:
a smartcard controller;
an inductive element to interact with a near field communication (NFC) reader designed to transmit data using an interrogating radio frequency field and receive data in frequency sidebands that result from load modulation; and
an active transmit driver circuit coupled between the smartcard controller and the inductive element to form a signal that mimics the frequency sidebands.
2. The apparatus of claim 1 wherein the inductive element is tuned to be resonant at 13.56 MHz.
3. The apparatus of claim 1 wherein the sideband frequencies are above and below 13.56 MHz.
4. The apparatus of claim 1 wherein the active transmit driver circuit comprises a modulator.
5. The apparatus of claim 4 wherein the active transmit driver circuit further comprises an amplifier.
6. The apparatus of claim 1 wherein interaction with an NFC reader effects mobile payments.
7. The apparatus of claim 1 wherein the apparatus comprises a mobile phone.
8. The apparatus of claim 1 wherein the apparatus comprises a mobile computing device.
9. The apparatus of claim 1 wherein the apparatus comprises an integrated circuit.
10. An apparatus comprising:
a smartcard controller; and
an active transmit driver circuit coupled to the smartcard controller, the active transmit circuit configured to form a signal that mimics frequency sidebands that would otherwise be generated by load modulating an inductive element when in the presence of an interrogating radio frequency (RF) field emitted by a near field communication (NFC) reader.
11. The apparatus of claim 10 wherein the active transmit driver circuit comprises a modulator.
12. The apparatus of claim 11 wherein the active transmit driver circuit further comprises an amplifier.
13. The apparatus of claim 10 wherein interaction with an NFC reader effects mobile payments.
14. The apparatus of claim 10 wherein the apparatus comprises a mobile phone.
15. The apparatus of claim 10 wherein the apparatus comprises an integrated circuit.
16. An apparatus comprising:
a smartcard controller;
an inductive element to interact with a near field communication (NFC) reader when in the presence of an interrogating radio frequency field at 13.56 Mhz; and
an active transmit driver circuit coupled between the smartcard controller and the inductive element to form frequency sidebands above and below 13.56 MHz.
17. The apparatus of claim 16 wherein the active transmit driver circuit comprises a modulator.
18. The apparatus of claim 17 wherein the active transmit driver circuit further comprises an amplifier.
19. The apparatus of claim 16 wherein the apparatus comprises a mobile phone.
20. The apparatus of claim 16 wherein the apparatus comprises an integrated circuit.