RFID tags combining signals received from multiple RF ports

• US 7,525,438 B2
• Filed: 05/15/2007
• Issued: 04/28/2009
• Est. Priority Date: 03/31/2004
• Status: Active Grant

• Current Assignee: Impinj, Inc.
• Original Assignee: Impinj, Inc.
• Inventors: Oliver, Ronald A., Hyde, John D., Onen, Omer
• Primary Examiner(s): Mullen; Thomas J
• Application Number:
  US11/803,995
• Publication Number:
  US 20070216533A1
• Time in Patent Office: 714 Days
• Field of Search: 340/572.1, 340/572.4, 340/572.7, 340/10.1, 455/41.1, 455/41.2, 342361-366
• US Class Current: 340/572.1
• 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 19/07767 the first and second communication means being two different antennas types, e.g. dipole and coil type, or two antennas of the same kind but operating at different frequencies

Abstract

Circuits, devices and methods for use in RFID tags include receiving multiple RF signals from multiple ports. The signals are added after some processing, to produce a single combined signal. Additional components process the single combined signal by itself.

Claims

1. A device for use in an RFID tag comprising:

means for generating a combined signal from a first signal received at a first RF port (first received signal) and a second signal received at a second RF port (second received signal);

means for generating a digital signal from the combined signal, the means for generating the digital signal including means for detecting peaks from the combined signal and means for comparing a version of the combined signal to a version of the detected peaks; and

means for generating a first processed signal from the first received signal,

wherein the first processed signal is used to generate the combined signal.

2. The device of claim 1, wherein

the means for generating the first processed signal includes an envelope detector.

3. A device for use in an RFID tag comprising:

means for generating a combined signal from a first signal received at a first RF port (first received signal) and a second signal received at a second RF port (second received signal);

means for generating a digital signal from the combined signal, the means for generating the digital signal including means for detecting an average value of the combined signal and means for comparing a version of the combined signal to a version of the detected average value; and

means for generating a first processed signal from the first received signal,

wherein the first processed signal is used to generate the combined signal.

4. The device of claim 3, wherein

the means for generating the first processed signal includes an envelope detector.

5. A device for use in an RFID tag comprising:

means for receiving a first signal at a first RF port (first received signal);

means for receiving a second signal at a second RF port (second received signal);

means for generating a first processed signal from the first received signal, the means for generating a first processed signal including a first envelope detector;

means for generating a second processed signal from the second received signal, the means for generating the second processed signal including a second envelope detector;

means for generating a combined signal from the first processed signal and the second processed signal; and

means for generating a digital signal from the combined signal.

6. The device of claim 5, wherein

the means for generating the combined signal includes an adder.

9. The method of claim 6, further comprising:

generating a second processed signal from the second received signal; and

wherein the generating the combined signal includes using the second processed signal to generate the combined signal.

10. The method of claim 9, wherein

the generating the combined signal includes adding the first processed signal and the second processed signal.

11. The method of claim 10, wherein

the generating the combined signal is performed at a node.

12. The method of claim 11, further comprising:

storing charge at the node.

13. The method of claim 12, further comprising:

discharging charge from the charge stored at the node.

7. A method for using a circuit of an RFID tag, comprising:

receiving a first signal at a first RF port (first received signal);

receiving a second signal at a second RF port (second received signal);

generating a combined signal from the first received signal and the second received signal;

generating a digital signal from the combined signal, the digital signal being generated by detecting peaks from the combined signal and comparing a version of the combined signal to a version of the detected peaks; and

generating a first processed signal from the first received signal, wherein the generating the combined signal includes

using the first processed signal to generate the combined signal.

8. The method of claim 7, wherein

the generating the first processed signal is performed by detecting an envelope of the first received signal.

14. A method for using a circuit of an RFID tag, comprising:

receiving a first signal at a first RF port (first received signal);

receiving a second signal at a second RF port (second received signal);

generating a combined signal from the first received signal and the second received signal;

generating a digital signal from the combined signal, the digital signal being generated by detecting an average value of the combined signal and comparing a version of the combined signal to a version of the detected average value; and

generating a first processed signal from the first received signal, wherein the generating the combined signal includes

using the first processed signal to generate the combined signal.

15. The method of claim 14, wherein

the generating the first processed signal is performed by detecting an envelope of the first received signal.

16. The method of claim 15, further comprising:

generating a second processed signal from the second received signal; and

wherein the generating the combined signal includes using the second processed signal to generate the combined signal.

17. The method of claim 16, wherein

the generating the combined signal includes adding the first processed signal and the second processed signal.

18. The method of claim 17, wherein

the generating the combined signal is performed at a node.

19. The method of claim 18, further comprising:

storing charge at the node.

20. The method of claim 19, further comprising:

discharging charge from the charge stored at the node.