DEVICES EMPLOYING MODULATOR SWITCHING AND METHODS THEREOF

• US 20110304432A1
• Filed: 06/11/2010
• Published: 12/15/2011
• Est. Priority Date: 06/11/2010
• Status: Active Grant

• Current Assignee: Zest Labs, Inc.
• Original Assignee: Intelleflex Corporation
• Inventors: Panchalan, Prasad, Farrell, Edward M.
• Granted Patent: US 8,823,493 B2
• Time in Patent Office: Days
• US Class Current: 340/10.1
• 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 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: G06K 7/10009 sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves

Abstract

In one embodiment, a RFID reader circuit includes a RF source input in a transmitting path, a RF modulator in parallel with a bypass, the RF modulator and the bypass being selectively coupled to the RF source input, at least one switch for selectively coupling an output of the RF modulator to the transmitting path, and a RF power amplifier in the transmitting path. In another embodiment, a RFID system includes a plurality of RFID tags, and a RFID reader, the RFID reader comprising a RFID reader circuit. The circuit includes a RF source input in a transmitting path, a RF modulator in parallel with a bypass, the RF modulator and the bypass being selectively coupled to the RF source input, at least one switch for selectively coupling an output of the RF modulator to the transmitting path, and a RF power amplifier in the transmitting path.

Claims

1. A Radio Frequency Identification (RFID) reader circuit, the reader circuit comprising:

a Radio Frequency (RF) source input in a transmitting path;

a RF modulator in parallel with a bypass, the RF modulator and the bypass being selectively coupled to the RF source input;

at least one switch for selectively coupling an output of the RF modulator to the transmitting path; and

a RF power amplifier in the transmitting path.

2. The RFID reader circuit of claim 1, wherein the reader circuit is adapted for monostatic operation.

3. The RFID reader circuit of claim 2, further comprising:

a signal splitter module coupled to a reader antenna lead; and

a low noise amplifier in the receiving path,

wherein an input of the signal splitter module is coupled to an output of the RF power amplifier,

wherein an output of the signal splitter module is coupled to an input of the low noise amplifier, and

wherein the reader antenna lead is for coupling to a reader antenna capable of sending and receiving signals.

4. The RFID reader circuit of claim 3, further comprising:

a first RF bandpass filter coupled between the RF source input and a mixer module; and

a second RF bandpass filter coupled between the reader antenna lead and the mixer module,

wherein the mixer module multiplies a first signal from the first RF bandpass filter with a second signal from the second RF bandpass filter to recover backscatter sidebands in the second signal.

5. The RFID reader circuit of claim 1, wherein the reader circuit is adapted for bistatic operation.

6. The RFID reader circuit of claim 5, further comprising:

a transmit antenna lead in the transmitting path for coupling to a transmit antenna capable of sending signals; and

a receive antenna lead in a receiving path for coupling to a receive antenna capable of receiving signals.

7. The RFID reader circuit of claim 6, further comprising:

a first RF bandpass filter coupled between the RF source input and a mixer module; and

a second RF bandpass filter in the receiving path coupled between the output of the receive antenna lead and the mixer module,

wherein the mixer module multiplies a first signal from the first RF bandpass filter with a second signal from the second RF bandpass filter to recover backscatter sidebands in the second signal.

8. The RFID reader circuit of claim 1, wherein the at least one switch is coupled to an output of the RF modulator.

9. The RFID reader circuit of claim 1, wherein one switch is coupled to an output of the RF modulator and one switch is coupled to an input of the RF modulator.

10. The RFID reader circuit of claim 1, wherein the RF modulator output is coupled during transmitting operations.

11. The RFID reader circuit of claim 1, wherein the RF modulator output is decoupled during receiving operations.

12. A Radio Frequency Identification (RFID) system, the system comprising:

a plurality of RFID tags; and

at least one RFID reader, the at least one RFID reader comprising a RFID reader circuit, the circuit comprising;

a Radio Frequency (RF) source input in a transmitting path;

a RF modulator in parallel with a bypass, the RF modulator and the bypass being selectively coupled to the RF source input;

at least one switch for selectively coupling an output of the RF modulator to the transmitting path; and

a RF power amplifier in the transmitting path.

13. The RFID system of claim 12, wherein the reader circuit is adapted for monostatic operation.

14. The RFID system of claim 13, wherein the RFID reader circuit further comprises:

a signal splitter module coupled to a reader antenna lead; and

a low noise amplifier in the receiving path,

wherein an input of the signal splitter module is coupled to an output of the RF power amplifier,

wherein an output of the signal splitter module is coupled to an input of the low noise amplifier, and

wherein the reader antenna lead is for coupling to a reader antenna capable of sending and receiving signals.

15. The RFID system of claim 14, wherein the RFID reader circuit further comprises:

a first RF bandpass filter coupled between the RF source input and a mixer module; and

a second RF bandpass filter coupled between the reader antenna lead and the mixer module,

wherein the mixer module multiplies a first signal from the first RF bandpass filter with a second signal from the second RF bandpass filter to cancel noise in the second signal.

16. The RFID system of claim 12, wherein the reader circuit is adapted for bistatic operation.

17. The RFID system of claim 16, wherein the RFID reader circuit further comprises:

a transmit antenna lead in the transmitting path for coupling to a transmit antenna capable of sending signals; and

a receive antenna lead in a receiving path for coupling to a receive antenna capable of receiving signals.

18. The RFID system of claim 17, wherein the RFID reader circuit further comprises:

a first RF bandpass filter coupled between the RF source input and a mixer module; and

a second RF bandpass filter in the receiving path coupled between the output of the receive antenna lead and the mixer module,

wherein the mixer module multiplies a first signal from the first RF bandpass filter with a second signal from the second RF bandpass filter to recover backscatter sidebands in the second signal.

19. The RFID system of claim 12, wherein the at least one switch is coupled to an output of the RF modulator.

20. The RFID system of claim 12, wherein one switch is coupled to an output of the RF modulator and one switch is coupled to an input of the RF modulator.

21. The RFID system of claim 12, wherein the RF modulator output is coupled during transmitting operations.

22. The RFID system of claim 12, wherein the RF modulator output is decoupled during receiving operations.

23. A method for reducing noise in a Radio Frequency Identification (RFID) reader circuit, the method comprising decoupling a RF modulator output from a transmitting path of a RFID reader circuit during receiving operations.

24. A Radio Frequency Identification (RFID) reader circuit, the reader circuit comprising:

a Radio Frequency (RF) source in a transmitting path;

a RF power amplifier in the transmitting path;

a low noise amplifier in a receiving path;

a first RF bandpass filter coupled between the RF source and a mixer module;

a second RF bandpass filter in the receiving path coupled to the mixer module;

a RF modulator selectively coupled to the RF source; and

a switch in series with the RF modulator for selectively coupling a RF modulator output to the transmitting path,

wherein the mixer module multiplies a first signal from the first RF bandpass filter with a second signal from the second RF bandpass filter to recover backscatter sidebands in the second signal.

25. The RFID reader circuit of claim 24, wherein the reader circuit is adapted for monostatic operation.

27. The RFID reader circuit of claim 24, wherein the reader circuit is adapted for bistatic operation.

28. The RFID reader circuit of claim 27, further comprising:

a transmit antenna lead in the transmitting path for coupling to a transmit antenna capable of sending signals; and

a receive antenna lead in a receiving path for coupling to a receive antenna capable of receiving signals.

29. The RFID reader circuit of claim 24, further comprising a switch coupled to an input of the RF modulator for selectively coupling the RF modulator to the transmitting path.

30. The RFID reader circuit of claim 24, wherein the RF modulator output is coupled during transmitting operations.

31. The RFID reader circuit of claim 24, wherein the RF modulator output is decoupled during receiving operations.

26. The RFID reader circuit of claim 26, further comprising:

a signal splitter module coupled to a reader antenna lead,

wherein an input of the signal splitter module is coupled to an output of the RF power amplifier,

wherein an output of the signal splitter module is coupled to an input of the low noise amplifier, and

wherein the reader antenna lead is for coupling to a reader antenna capable of sending and receiving signals.