System for identifying radio-frequency identification devices

• US 20070046433A1
• Filed: 08/28/2006
• Published: 03/01/2007
• Est. Priority Date: 08/30/2005
• Status: Active Grant

• Current Assignee: Somnath Mukherjee
• Original Assignee: Somnath Mukherjee
• Inventors: Mukherjee, Somnath
• Granted Patent: US 7,639,137 B2
• Time in Patent Office: Days
• US Class Current: 340/10.100
• CPC Class Codes: G06K 19/0672 with resonating marks
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer

Abstract

A system for identifying radio-frequency identification (RFID) devices is described. In one embodiment, RFID devices include an antenna and metallic pattern printed on a substrate. A probing platform is used to radiate the RFID devices with an electromagnetic signal (e.g., radio-frequency signal, microwave signal, etc.). Each RFID device generates a quantifiable backscatter depending on the unique impedance of the passive RFID device in response to the electromagnetic signal. The backscatter is employed to uniquely identify the passive RFID device'"'"'s impendence with respect to the probing platform uniquely characterized at predetermined frequencies of the electromagnetic signal.

Claims

1. A method of identifying a radio-frequency identification device, the method comprising:

transmitting a wireless signal that varies over a predetermined range of frequencies to a radio-frequency identification device; and

processing backscatter wireless signals reflected from the radio-frequency identification device according to the radio-frequency identification device'"'"'s predetermined impedance to determine a device signature.

2. The method of claim 1, wherein the wireless signal is swept over the predetermined range.

3. The method of claim 1, wherein transmitting the wireless signal comprises directing a signal in a beam toward the radio-frequency identification device.

4. The method of claim 1, wherein the device signature is associated with a frequency dependent phase shift of the backscatter wireless signals associated with the impedance.

5. The method of claim 1, further comprising mixing the backscatter signals with the transmitted wireless signal to form a intermediate frequency that comprises identification information associated with the impedance.

6. A method of distinguishing a radio-frequency identification device from a group of radio-frequency identification devices, the method comprising:

transmitting a wireless signal that varies over a predetermined range of frequencies to a plurality of radio-frequency identification devices, wherein at least one radio-frequency identification device of the plurality of radio-frequency identification devices includes a predetermined reflective impedance configured to reflect at least a portion of the wireless signal with a predetermined reflection pattern; and

determining a unique device signature associated with the predetermined reflective impedance from wireless signals backscattered from the at least one radio-frequency identification device in response to the transmitted wireless signal.

7. The method of claim 6, wherein at least two of the plurality of radio-frequency identification devices comprise a unique predetermined reflective impedance with respect to the plurality of radio-frequency identification devices.

8. The method of claim 6, wherein transmitting the wireless signal comprises sweeping the wireless signal over the predetermined range of frequencies at a predetermined sweep rate that is sufficient to provide a received signal at the probing platform responsive to a delay time between the transmitted signal and a received portion of the backscattered wireless signal.

9. The method of claim 6, wherein one or more of the plurality of radio-frequency identification devices are formed using a printing process.

10. A radio-frequency identification device system, the system comprising:

a transmitter configured to transmit a wireless signal over a predetermined frequency range;

at least one radio-frequency identification device configured to reflect and scatter at least a portion of the transmitted wireless signal in a pattern associated with the predetermined impedance of the at least one radio-frequency identification device; and

a receiver configured to process the portion of the wireless signal received from the at least one radio-frequency identification device to determine a unique device signature associated with the predetermined impedance of the at least one radio-frequency identification device.

11. The system of claim 10, wherein the wireless signal is a wideband signal.

12. The system of claim 10, further comprising a probing platform which comprises the transmitter and the receiver.

13. The system of claim 10, wherein the predetermined impedance of the at least one radio-frequency identification device defines a unique device signature.

14. The system of claim 10, wherein the system comprises a calibration circuit configured to automatically calibrate the system with regard to at least round trip delay or system related signal losses.

15. The system of claim 10, wherein the at least one radio-frequency identification device is a passive device that does not require converting the wireless signal to electrical power for operation.

16. The system of claim 10, wherein the calibration circuit is configured to substantially calibrate for wireless transmission issues associated with a transmission medium.

17. The system of claim 10, wherein the receiver is configured to determine at least one of range, azimuth, or elevation from the portion of the wireless signal scattered from the at least one radio-frequency identification device.

18. The system of claim 10, wherein the receiver is configured to discriminate between a plurality of radio-frequency identification devices using a unique device signature associated with each of the radio-frequency identification devices.

19. The system of claim 10, wherein the radio-frequency identification device is capable of operating in environments physically caustic to semiconductor devices.

20. The system of claim 19, wherein the environments comprises temperature environments physically damaging to semiconductor devices.

21. The system of claim 19, wherein the environments comprises chemical environments physically damaging to semiconductor devices.

22. The system of claim 10, wherein the radio-frequency identification device is capable of operating in wireless environments electrically caustic to semiconductor devices.

23. The system of claim 22, wherein the wireless environments comprise environments subject to electromagnetic pulse transmission sufficient to damage the operation of semiconductor devices.

24. The system of claim 22, wherein the wireless environments comprise environments subject to radiation sufficient to damage the operation of semiconductor devices.

25. The system of claim 10, wherein the radio-frequency identification device is capable of operating in an electrically interfering wireless environment.