Multi-Antenna Element Systems and Related Methods

• US 20080238684A1
• Filed: 03/27/2007
• Published: 10/02/2008
• Est. Priority Date: 03/27/2007
• Status: Active Grant

• Current Assignee: Round Rock Research LLC
• Original Assignee: Micron Technology, Inc.
• Inventors: Tuttle, John R.
• Granted Patent: US 8,031,054 B2
• Time in Patent Office: Days
• US Class Current: 340/572.7
• 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
• CPC Class Codes: G06K 19/07786 the antenna being of the HF type, such as a dipole
• CPC Class Codes: H01Q 1/2216 used in interrogator/reader equipment
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H01Q 9/04 Resonant antennas

Abstract

Multi-Antenna element systems and related methods. At least some of the illustrative embodiments comprise a radio frequency identification (RFID) tag comprising an antenna system. The antenna system comprises a ground plane, a first antenna element on a first side of the ground plane, and a second antenna element on a second side of the ground plane opposite first antenna element. The illustrative RFID tag further comprises a first radio frequency identification circuit coupled to the first antenna element.

Claims

1. A radio frequency identification (RFID) tag comprising:

an antenna system comprising;

a ground plane;

a first antenna element on a first side of the ground plane; and

a second antenna element on a second side of the ground plane opposite first antenna element;

a first radio frequency identification circuit coupled to the first antenna element.

2. The RFID tag as defined in claim 1 wherein the first radio frequency identification circuit also couples to second antenna element.

3. The RFID tag as defined in claim 2 further comprising a first isolation circuit coupled between the first antenna element and the radio frequency identification circuit, the first isolation circuit selectively isolates the first antenna element from the radio frequency identification circuit.

4. The RFID tag as defined in claim 3 further comprising a second isolation circuit coupled between the second antenna element and the radio frequency identification circuit, the second isolation circuit selectively isolates the second antenna element from the radio frequency identification circuit.

5. The RFID tag as defined in claim 3 wherein the first isolation circuit electrically isolates the first antenna element from the radio frequency identification circuit when the first antenna element is out of position to reliably receive an interrogating signal.

6. The RFID tag as defined in claim 1 further comprising a second radio frequency identification circuit coupled to the second antenna element.

7. The RFID tag as defined in claim 6 further comprising:

wherein the first radio frequency identification circuit, when queried by a reader, responds with an identification value; and

wherein the second radio frequency identification circuit, when queried by a reader, responds with an identification value.

8. The RFID tag as defined in claim 7 wherein the first radio frequency identification circuit couples to the second radio frequency identification circuit.

9. The RFID tag as defined in claim 1 wherein each of the first and second antenna elements comprises a patch of conductive material having a length and a width equal to or smaller than a length and width of the ground plane.

10. An apparatus comprising:

a first radiative patch with an internal feed point;

a second radiative patch with an internal feed point; and

a ground element disposed between the first and second radiative patches and electrically isolated from the radiative patches;

wherein the first and second radiative patches are configured to be driven at their respective feed points with a radio frequency signal.

11. The apparatus as defined in claim 10 further comprising a first layer of dielectric material coupled between the first radiative patch and the ground element.

12. The apparatus as defined in claim 11 further comprising a second layer of dielectric material coupled between the second radiative patch and the ground element.

13. The apparatus as defined in claim 10 wherein the first radiative patch is configured to be driven by a first radio frequency signal, and the second radiative patch is configured to be driven by a second radio frequency signal.

14. The apparatus as defined in claim 10 further comprising a first radio frequency identification circuit coupled to the first radiative patch, and when an interrogating signal is incident upon the first radiative patch, the first radio frequency identification circuit responds with a first value.

15. The apparatus as defined in claim 14 further comprising a second radio frequency identification circuit coupled to the second radiative patch, and when an interrogating signal is incident upon the second radiative patch, the second radio frequency identification circuit responds with a second value.

16. The apparatus as defined in claim 15 wherein the first and second values are the same.

17. The apparatus as defined in claim 15 wherein the first and second values are different.

18. The apparatus as defined in claim 15 wherein each of the first and second radio frequency identification circuit respond with their respective values by selective detuning of their respective radiative patches.

19. The apparatus as defined in claim 10 further comprising a radio frequency identification circuit coupled to both the first and second radiative patches, and when an interrogating signal is incident upon at least one of the radiative patches, the radio frequency identification circuit responds with a value.

20. The apparatus as defined in claim 19 further comprising a first buffer coupled between the first radiative patch and the radio frequency identification circuit, the first buffer selectively isolates the first radiative patch from the radio frequency identification circuit.

21. The apparatus as defined in claim 20 further comprising a second buffer coupled between the second radiative patch and the radio frequency identification circuit, the second buffer selectively isolates the first radiative patch from the radio frequency identification circuit.

22. The apparatus as defined in claim 19 wherein the radio frequency identification circuit responds with the value by selective detuning of at least one of the radiative patches.

23. The apparatus as defined in claim 10 further comprising:

wherein the first radiative patch comprises a centroid axis normal to a plane defined by the first radiative patch; and

wherein the second radiative patch comprises a centroid axis normal to a plane defined by the second radiative patch and substantially coaxial with the centroid axis of the first radiative patch.

24. A method comprising:

isolating a first antenna element of a radio frequency identification (RFID) tag from a RFID circuit of the RFID tag; and

transmitting a value responsive to an interrogating signal, the transmitting from a second antenna element of the RFID tag, the second antenna element coupled to the RFID circuit.

25. The method as defined in claim 24 wherein isolating further comprises electrically de-coupling the first antenna element from the RFID circuit.

26. The method as defined in claim 25 wherein electrically decoupling further comprises rectifying the interrogating signal received by the first antenna element, and refraining from coupling the first antenna element to the RFID circuit when an amount of power derived from rectifying the interrogating signal is below a predetermined threshold.

27. The method as defined in claim 24 wherein isolating further comprises providing a RFID circuit for the first antenna element different than the RFID circuit coupled to the second antenna element.

28. A system comprising:

a first means for receiving and sending electromagnetic waves, the first means for receiving having an internally disposed means for insertion of a driving signal;

a second means for receiving and sending electromagnetic waves, the second means for receiving having an internally disposed means for insertion of a driving signal; and

a means for limiting directionality of electromagnetic waves, the means for limiting disposed between the first and second means for receiving, and the means for limiting electrically isolated from the first and second means for receiving;

wherein the first and second means for receiving are configured to be driven at their respective means for insertion with a radio frequency signal.

29. The system as defined in claim 28 further comprising:

a first means for responding to interrogating signals, the first means for responding coupled to the first means for receiving; and

a second means for responding to interrogating signals, the second means for responding coupled to the second means for receiving.

30. The system as defined in claim 29 wherein the first and second means for responding, in response to interrogating signals, one or more selected from the group consisting of:

respond identically;

or respond such that the first means for receiving is distinguishable from the second means for receiving.

31. The system as defined in claim 28 further comprising a means for responding to interrogating signals, the means for responding coupled to both the first and second means for receiving.

32. The system as defined in claim 31 further comprising:

a first means for electrically isolating the first means for receiving and the first means for decoding; and

a second means for electrically isolating the second means for receiving and the second means for decoding.