Multi-frequency communication system and method

• US 6,745,008 B1
• Filed: 06/06/2000
• Issued: 06/01/2004
• Est. Priority Date: 06/06/2000
• Status: Expired due to Term

• Current Assignee: Battelle Memorial Institute
• Original Assignee: Battelle Memorial Institute
• Inventors: Gilbert, Ronald W., Carrender, Curtis Lee
• Primary Examiner(s): Tran, Sinh
• Assistant Examiner(s): Afshar, Kamran
• Application Number:
  US09/589,000
• Time in Patent Office: 1,456 Days
• Field of Search: 340/572.4, 340/572.2, 340/10.1, 340/10.3, 340/10.4, 340/10.41, 340/825.54, 340/152.R, 340/168, 340/572.8, 340/572.5, 375/283, 370/527, 370/204, 370/205, 455/45, 455/69, 455/911.1, 455/412-42, 455/20, 455/403, 455/151.2, 455/73, 455/90.1, 455/106, 455/227, 455/67.1, 379/58, 379/93, 379/89, 342/42-51, 342/30-32
• US Class Current: 455/41.1
• CPC Class Codes: A01K 11/006 Automatic identification systems for animals, e.g. electronic devices, transponders for animals identification systems for access to feeding pens A01K1/0209; ear tags with electronic identification means A01K11/004
• 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 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10069 the collision being resolved in the frequency domain, e.g. by hopping from one frequency to the other frequency hopping or spread spectrum techniques H04B7/00

Abstract

A multi-frequency RFID remote communication system is provided that includes a plurality of RFID tags configured to receive a first signal and to return a second signal, the second signal having a first frequency component and a second frequency component, the second frequency component including data unique to each remote RFID tag. The system further includes a reader configured to transmit an interrogation signal and to receive remote signals from the tags. A first signal processor, preferably a mixer, removes an intermediate frequency component from the received signal, and a second processor, preferably a second mixer, analyzes the IF frequency component to output data that is unique to each remote tag.

Claims

1. A remote communication device, comprising:

a communication circuit configured to receive a first signal and to return a reflected second signal responsive to the first signal, the second signal modulated by a first modulation frequency and a second modulation frequency, the second modulation frequency imposed on the first modulation frequency and comprising at least one data signal unique to the communication device, wherein the second modulation frequency comprises first and second data signals, wherein the first data signal is generated by a first data signal generator and the second data signal is generated by a second data signal generator, wherein the first and second data signals are generated at frequencies different from one another, wherein the communication circuit is further configured to generate a supply voltage from the first signal.

2. The device of claim 1, wherein the first and second signals comprise radio frequency signals.

3. The device of claim 1, wherein the at least one data signal generator comprises a variable frequency signal generator.

4. The device of claim 2 wherein the communication circuit is further configured to receive an energy signal from an energy signal source and to generate a supply voltage from the energy signal.

5. The device of claim 2, wherein the communication circuit is further configured to activate and deactivate upon receipt of remote activation and deactivation signals, respectively.

6. A remote communication device, comprising:

an antenna for receiving at least a first signal and returning a reflected second signal; and

a signal processing circuit coupled to the antenna for generating the second signal in response to the first signal, the signal processing circuit comprising at least a first modulation circuit for modulating the second signal at a primary frequency and a second modulation circuit for modulating the second signal at an at least one intermediate frequency imposed on the primary frequency that includes a first data signal and a second data signal unique to the remote communication device, wherein the at least one intermediate frequency is a frequency higher than the frequency of the primary frequency, wherein the antenna and the signal processing circuit are configured to receive an energy signal and to generate a supply voltage from the energy signal for supplying current to the signal processing circuit.

7. The device of claim 6, wherein the first and second signals comprise radio frequency signals.

8. The device of claim 7, wherein the primary frequency comprises first and second states, and the at least one intermediate frequency is imposed on the first state.

9. The device of claim 7, wherein the primary frequency has first and second states, and a first intermediate frequency is imposed on the first state and a second intermediate frequency is imposed on the second state.

10. A reader for communicating with a plurality of remote communication devices at a plurality of intermediate frequencies, comprising:

an antenna for receiving a plurality of remote reflected signals each remote reflected signal modulated at a first intermediate frequency and a second intermediate frequency imposed on the first intermediate frequency; and

a first receiving circuit coupled to the antenna for extracting data simultaneously from each of the remote reflected signals, wherein the first receiving circuit comprises at least one processing circuit for extracting data from each of the remote reflected signals, each at least one processing circuit configured to process a remote reflected signal of a predetermined frequency, further comprising a second receiving circuit for extracting data simultaneously from each of the remote reflected signals that are not received in the first receiving circuit due to a phase shift in the remote reflected signals, the second receiving circuit coupled to the antenna in parallel with the first receiving circuit and having at least one processing circuit configured to process a remote reflected signal of a predetermined frequency, further comprising a transmitting circuit coupled to the antenna for transmitting an interrogation signal to the first and second remote communication devices, wherein the antenna comprises a transmitting antenna coupled to the transmitting circuit and a receiving antenna coupled to the first and second receiving circuits, further comprising a low noise amplifier coupled between the receiving antenna and the first and second receiving circuits, further comprising a first divide-by-two circuit coupled between the transmitting antenna and the first and second receiving circuits and a second divide-by-two circuit coupled between the receiving antenna and the first and second receiving circuits.

11. The reader of claim 10, further comprising a low noise amplifier coupled between the receiving antenna and the second divide-by-two circuit.

12. The reader of claim 10, wherein the first and second receiving circuits each comprise a first processing circuit for extracting an intermediate frequency signal from each of the plurality of remote reflected signals, and a second processing circuit for extracting data from the intermediate frequency signal.

13. The reader of claim 12, wherein the second processing circuit comprises a plurality of mixer circuit, each configured to extract data from a single intermediate frequency different from the other of the plurality of mixer circuits.

14. A multi-frequency communication system, comprising:

a plurality of remote communication devices, each remote communication device comprising;

an antenna for receiving at least a first signal and returning a remote reflected signal; and

a processing circuit coupled to the antenna for generating the remote reflected signal in response to the first signal, the processing circuit comprising at least a first modulation circuit for returning the remote reflected signal at a primary frequency and a second modulation circuit for modulating the remote reflected signal at at least one intermediate frequency imposed on the primary frequency and unique to that remote communication device, and to include a data signal unique to that remote communication device, wherein the at least one intermediate frequency is a frequency higher than the frequency of the primary frequency, wherein the antenna and the processing circuit are configured to receive an energy signal and to generate a supply voltage from the energy signal for supplying current to the signal processing circuit; and

a reader for communicating with the plurality of remote communication devices at multiple frequencies, the reader comprising;

an antenna for receiving the remote reflected signals at multiple frequencies; and

a first receiving circuit coupled to the antenna for extracting data simultaneously from each of the remote reflected signals.

15. The system of claim 14, wherein the first signal and the remote reflected signals comprise radio frequency signals.

16. The system of claim 15, wherein the first receiving circuit comprises at least one processing circuit, each at least one processing circuit configured to process a remote reflected signal of a predetermined frequency.

17. The system of claim 16, wherein the at least one processing circuit comprises a first processing circuit for extracting the at least one intermediate frequency from the remote reflected signal and a second processing circuit for extracting data from the at least one intermediate frequency signal.

18. The system of claim 17, wherein the primary frequency comprises first and second states, and the at least one intermediate frequency is imposed on the first state.

19. The system of claim 17, wherein the remote reflected signal comprises the primary frequency and first and second intermediate frequencies, and further wherein the second processing circuit of each of the at least one processing circuit is configured to extract data from the first and second intermediate frequencies.

20. The system of claim 19 wherein the primary frequency has first and second states, and the first intermediate frequency is imposed on the first state and the second intermediate frequency is imposed on the second state.

21. The system of claim 17, wherein the reader further comprises a second receiving circuit for extracting data simultaneously from each of the remote reflected signals that are not received in the first receiving circuit due to phase shifts.

22. The system of claim 21, wherein the reader further comprises a transmitting circuit coupled to the antenna for transmitting the first signal to the remote communication devices.

23. The system of claim 22, wherein the antenna comprises a transmitting antenna coupled to the transmitting circuit and a receiving antenna coupled to the receiving circuit.

24. The system of claim 23, further comprising a low noise amplifier coupled between the receiving antenna and the first and second receiving circuits.

25. The system of claim 22, further comprising a first divide-by-two circuit coupled between the transmitting antenna and the first and second receiving circuits and a second divide-by-two circuit coupled between the receiving antenna and the first and second receiving circuits.

26. The system of claim 25, further comprising a low noise amplifier coupled between the receiving antenna and the second divide-by-two circuit.

27. A method for remote communication between a plurality of remote communication devices and a reader, the method comprising:

receiving an interrogation signal at the plurality of remote communication devices;

reflecting from each remote communication device a remote reflected signal responsive to the interrogation signal, the remote reflected signal of each remote communication device having a frequency different from the remote reflected signal of the other remote communication devices, each remote reflected signal modulated by a first modulation circuit at a primary frequency and by a second modulation circuit at an at least one intermediate frequency imposed on the primary frequency, wherein the at least one intermediate frequency is a frequency higher than the frequency of the primary frequency;

generating a supply voltage for the first and second modulation circuits from the interrogation signal at each remote communication device;

receiving the remote reflected signals from each remote communication device; and

extracting data from each remote reflected signal.

28. The method of claim 27, wherein before receiving the interrogation signal, comprising transmitting the interrogation signal.

29. The method of claim 28, wherein generating each remote reflected signal comprises generating a multi-frequency remote reflected signal to have a primary frequency and an intermediate frequency, the intermediate frequency including a data signal unique to each remote communication device;

and extracting the data from the remote reflected signal comprises removing the extracting the data from the intermediate frequency.

30. The method of claim 28, wherein each of the multi-frequency signals is received and processed simultaneously.