RFID reader device having closely packed antennas

• US 20060165039A1
• Filed: 03/27/2006
• Published: 07/27/2006
• Est. Priority Date: 01/30/2003
• Status: Active Grant

• Current Assignee: Valtrus Innovations Limited (f/k/a Dolya Holdco 9 Limited) (Key Patent Innovations Limited)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Robinson, Ian, Brignone, Cyril, Lyon, Geoff, McReynolds, Alan
• Granted Patent: US 7,686,229 B2
• Time in Patent Office: Days
• US Class Current: 370/334
• CPC Class Codes: G06F 15/173 using an interconnection network, e.g. matrix, shuffle, pyramid, star, snowflake
• CPC Class Codes: G06K 17/00 Methods or arrangements for effecting co-operative working between equipments covered by two or more of main groups G06K1/00 - G06K15/00, e.g. automatic card files incorporating conveying and reading operations
• CPC Class Codes: G06K 19/077 Constructional details, e.g. mounting of circuits in the carrier
• CPC Class Codes: G06K 19/07758 arrangements for adhering the record carrier to further objects or living beings, functioning as an identification tag
• CPC Class Codes: G06K 7/00 Methods or arrangements for sensing record carriers, e.g. for reading patterns methods or arrangements for marking the record carrier in digital fashion G06K1/00; pattern recognition G06F18/00; arrangements for image or video recognition or understanding G06V10/00; character recognition, recognising digital ink or document-oriented image-based pattern recognition G06V30/00
• 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: G06Q 20/20 Point-of-sale [POS] network systems
• CPC Class Codes: G06Q 20/208 Input by product or record sensing, e.g. weighing or scanner processing
• CPC Class Codes: G06Q 20/367 involving electronic purses or money safes

Abstract

A reader device for locating and tracking multiple tags includes a plurality of closely packed antenna circuits and at least one controller configured to control the plurality of closely packed antenna circuits. The at least one controller is configured to activate one or more of the antenna circuits to generate at least one resonance signal field configured to interrogate at least one tag associated with the one or more active antenna circuits while substantially preventing or reducing cross-coupling of signals between the one or more active antenna circuits and at least one antenna circuit within the at least one resonance signal field to a sufficiently low level, wherein the sufficiently low level substantially prevents misreads from unwanted tags, to thereby track the multiple tags in a substantially controlled manner.

Claims

1. A reader device for locating and tracking multiple tags, said reader device comprising:

a plurality of closely packed antenna circuits;

at least one controller configured to control the plurality of closely packed antenna circuits; and

wherein the at least one controller is configured to activate one or more of the antenna circuits to generate at least one resonance signal field configured to interrogate at least one tag while substantially preventing or reducing cross-coupling of signals between the one or more active antenna circuits and at least one antenna circuit within the at least one resonance signal field to a sufficiently low level, wherein the sufficiently low level substantially prevents misreads from unwanted tags, to thereby track the multiple tags in a substantially controlled manner.

2. The reader device according to claim 1, wherein the plurality of closely packed antenna circuits comprise at least one configuration designed to substantially prevent or reduce cross-coupling with one or more activated antenna circuits.

3. The reader device according to claim 2, wherein the plurality of closely packed antenna circuits comprise RLC circuits, wherein the resistors are employable to control Q-factors for the antenna circuits.

4. The reader device according to claim 3, further comprising:

a complementary pair of MOSFET transistors positioned to generate drive signals to the RLC circuits.

5. The reader device according to claim 1, wherein the plurality of closely packed antenna circuits comprise switches positioned between at least one of a capacitor and a ground and an inductor and a ground, and wherein the switches are configured to be opened for inactivated ones of the plurality of closely packed antenna circuits.

6. The reader device according to claim 1, wherein the plurality of antenna circuits comprise respective LC circuits, wherein a capacitor of each of the LC circuits comprises a variable capacitor, and wherein the at least one controller is configured to vary the capacitance of and thereby detune the LC circuits located within the resonance signal field of the active antenna circuit.

7. The reader device according to claim 1, wherein at least one of the plurality of closely packed antenna circuits is configured to interrogate a plurality of the tags to thereby reduce the resolution of the tag locations to one or more positions.

8. The reader device according to claim 1, wherein at least one of the plurality of closely packed antenna circuits overlaps at least one other closely packed antenna circuit to thereby occupy common space and energize shared spatial regions with the at least one other closely packed antenna circuit.

9. The reader device according to claim 8, wherein the number of overlapping plurality of closely packed antenna circuits is selected to vary the resolution in determining the locations of the tags.

10. The reader device according to claim 1, wherein the tags are associated with respective assets, wherein the assets comprise one or more of electronic equipment, cables, and consumer goods.

11. A method for locating and tracking tags with a reader device, said reader device having at least one antenna circuit, said method comprising:

activating the at least one antenna circuit to generate a resonance signal field configured to interrogate a tag associated with the active at least one antenna circuit; and

decoupling at least one other antenna circuit positioned within the resonance signal field of the active at least one antenna circuit to reduce cross-coupling of signals between the active at least one antenna circuit and the at least one other antenna circuit positioned within the resonance signal field to a sufficiently low level, wherein the sufficiently low level substantially prevents misreads from unwanted tags.

12. The method according to claim 11, further comprising:

determining whether a signal is returned by a tag associated with the active at least one antenna circuit;

storing an indication that an asset associated with the tag is present at a location corresponding to the active at least one antenna circuit in response to a signal being returned by the tag associated with the active at least one antenna circuit; and

storing an indication that the location corresponding to the active at least one antenna circuit does not contain an asset in response to a signal not being returned.

13. The method according to claim 12, wherein the at least one other antenna circuit comprises an RLC circuit and wherein decoupling the at least one other antenna circuit further comprises varying the Q-factor for the RLC circuit.

14. The method according to claim 11, wherein the at least one antenna circuit overlaps the at least one other antenna circuit, the method further comprising:

sequentially activating the overlapping antenna circuits;

correlating indications received by the overlapping antenna circuits; and

determining locations of the tags based upon the correlations.

15. The method according to claim 11, wherein the at least one antenna circuit is configured to interrogate a plurality of tag locations, said method further comprising:

determining a position of a tag to within multiple locations of the plurality of tag locations.

16. The method according to claim 11, wherein the reader device has a plurality of closely packed antenna circuits, wherein the tags are associated with respective assets, wherein the plurality of closely packed antenna circuits are positioned to emit resonance signal fields toward respective tags, and wherein the method further comprises sequentially activating the plurality of closely packed antenna circuits while decoupling at least one of the plurality of antenna circuits positioned with in the resonance signal field of the active antenna circuit to thereby determine the locations of the assets.

17. An apparatus for tracking a plurality of electronic devices having a plurality of radio frequency (RF) tags associated therewith, said apparatus comprising:

a rack having a plurality bays, said plurality of bays housing the plurality of electronic devices; and

at least one reader device having at least one antenna circuit, wherein the at least one reader device is configured to interrogate a plurality of RF tags to thereby determine at least one of a location and presence of an electronic device located in a first bay and an electronic device located in a second bay of the rack.

18. The apparatus according to claim 17, wherein the at least one reader device comprises a plurality of antenna circuits.

19. The apparatus according to claim 17, wherein the at least one antenna circuit is configured to interrogate a plurality of tags.

20. The apparatus according to claim 17, wherein the at least one antenna circuit overlaps at least one other antenna circuit to thereby occupy common space and energize shared spatial regions with the at least one other antenna circuit.