RFID device tester and method

• US 20040160233A1
• Filed: 02/13/2003
• Published: 08/19/2004
• Est. Priority Date: 02/13/2003
• Status: Active Grant

• Current Assignee: Avery Dennison Retail Information Services LLC (Avery Dennison Corporation)
• Original Assignee: Avery Dennison Corporation
• Inventors: Forster, Ian J.
• Granted Patent: US 7,225,992 B2
• Time in Patent Office: Days
• US Class Current: 324/667
• 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 7/0095 Testing the sensing arrangement, e.g. testing if a magnetic card reader, bar code reader, RFID interrogator or smart card reader functions properly testing of electrical circuits G01R31/28
• CPC Class Codes: G06K 7/10465 the interrogation device being capable of self-diagnosis, e.g. in addition to or as part of the actual interrogation process testing of electrical circuits in general G01R31/28
• CPC Class Codes: Y10T 29/49004 including measuring or testing of device or component part

Abstract

An RFID device tester includes coupling elements for capacitively coupling a reader to an RFID device to be tested. The reader may power the RFID device by sending an outgoing signal, such as an outgoing AC power signal, which may be rectified and/or reflected by the RFID device, if the RFID device is operating properly. The outgoing signal may have a frequency that is different from the resonant frequency of an antenna of the RFID device. A reader in the RFID device tester detects the reflected and/or transmitted signal to confirm proper operation of the RFID device. The RFID device tester may be used as part of a roll-to-roll process, to individually test RFID devices on a roll of material. By utilizing short-range capacitive coupling, difficulties caused by simultaneous activation of multiple RFID devices may be reduced or avoided.

Claims

1. A method of testing a radio frequency identification (RFID) device, comprising:

capacitively coupling an RFID device tester to an antenna of the RFID device;

generating an outgoing signal from the RFID device tester;

using the outgoing signal to power the RFID device;

generating a return signal in the RFID device; and

detecting a return signal, via a reader that is part of the tester.

2. The method of claim 1, wherein the generating the outgoing signal includes generating the outgoing signal at a signal frequency that is different from a natural resonant frequency of the antenna.

3. The method of claim 2, further comprising, prior to the generating, shifting an optimum operating frequency of the antenna from the natural resonant frequency of the antenna to a shifted resonant frequency.

4. The method of claim 3, wherein the shifting the optimum operating frequency includes decreasing the optimum operating frequency.

5. The method of claim 4, wherein the decreasing the optimum operating frequency includes bringing dielectric elements in close proximity to the antenna elements.

6. The method of claim 4, wherein the decreasing the optimum operating frequency includes overlapping portions of the antenna elements with dielectric elements.

7. The method of claim 6, wherein the dielectric elements include a ceramic material.

8. The method of claim 7, wherein the ceramic material includes a material selected from the group consisting of barium tetra titanate and titanium oxide.

9. The method of claim 4, wherein the decreasing the optimum operating frequency includes bringing electrically-conducting elements in close proximity to the antenna elements.

10. The method of claim 3, wherein the shifting the optimum operating frequency includes increasing the optimum operating frequency.

11. The method of claim 10, wherein the increasing the optimum operating frequency includes bringing electrically-conducting elements in close proximity to antenna elements of the antenna.

12. The method of claim 3, wherein the shifting includes bringing the RFID device and at least part of the tester in close proximity.

13. The method of claim 3, wherein the generating the signal frequency includes generating a frequency that is substantially the same as the shifted resonant frequency.

14. The method of claim 1,

wherein the RFID device tester includes coupling elements electrically connected to the reader;

wherein the antenna of the RFID device includes antenna elements; and

wherein the capacitively coupling includes aligning the coupling elements with respective of the antenna elements.

15. The method of claim 14,

wherein the coupling elements are attached to a dielectric layer;

and

wherein the aligning includes having portions of the dielectric layer between the coupling elements and the antenna elements.

16. The method of claim 14,

wherein the coupling elements are part of a roller;

wherein the RFID device is part of a roll material; and

wherein the aligning includes bringing the portion of the roll material having the RFID device into alignment with the coupling elements as the roller rotates.

17. The method of claim 16, wherein the aligning is part of a roll-to-roll process.

18. The method of claim 1, wherein the RFID device is part of a sheet or roll with other RFID devices thereupon.

19. The method of claim 18, wherein the capacitively coupling includes shifting the relative positions of the RFID device tester and the sheet or roll.

20. The method of claim 19, wherein the shifting includes moving the sheet or roll.

21. The method of claim 20,

wherein the sheet or roll is a roll;

and

wherein the moving the roll is part of a roll-to-roll process.

22. The method of claim 19, wherein the shifting includes moving the RFID device tester.

23. The method of claim 22,

wherein the RFID device tester has circular coupling elements, and

wherein the moving the RFID device tester includes rolling the RFID device tester over the sheet or roll.

24. The method of claim 1, wherein the detecting the return signal includes:

capacitively transmitting the return signal from the antenna to coupling elements of the RFID device tester; and

forwarding the return signal from the coupling elements to the reader.

25. The method of claim 24, wherein the forwarding includes forwarding the return signal past a resistor coupled to a pair of transmission lines electrically connecting the reader and respective of the coupling elements.

26. A method of testing a radio frequency identification (RFID) strap, comprising:

capacitively coupling an RFID device tester to conductive leads of the RFID strap;

generating an outgoing signal from the RFID device tester;

using the outgoing signal to power the RFID strap;

generating a return signal in the RFID strap; and

detecting a return signal, via a reader that is part of the tester.

27. A radio frequency identification (RFID) device tester comprising:

a reader;

a pair of electrically-conductive coupling elements;

a pair of transmission lines electrically connecting respective of the coupling elements to the reader; and

a resistor connected to both of the transmission lines, between the reader and the coupling elements.

28. The device tester of claim 27, further comprising dielectric materials on outer surfaces of each of the coupling elements.

29. The device tester of claim 28, wherein the dielectric materials are portions of a dielectric layer.

30. The device tester of claim 27, wherein the coupling elements are substantially planar.

31. The device tester of claim 27, wherein the coupling elements are hoop-shaped.

32. The device tester of claim 27, further comprising dielectric elements for shifting an optimum operating frequency of RFID devices placed in close proximity to the device tester.

33. The device tester of claim 32, wherein the dielectric elements include ceramic elements.

34. The device tester of claim 27, further comprising additional electrically-conducting elements for shifting an optimum operating frequency of RFID devices placed in close proximity to the device tester.

35. The device tester of claim 27, in combination with an RFID device, wherein the RFID device includes an antenna that is capacitively coupled to the coupling elements.

36. The device tester of claim 27, wherein the coupling elements are part of a roller.

37. The device tester of claim 36, wherein the coupling elements are on an outer surface of the roller.

38. The device tester of claim 37,

further comprising additional pairs of coupling elements on the outer surface of the roller,

wherein the additional pairs of coupling elements are also coupled to the reader.

39. The device tester of claim 38, wherein the pairs of coupling elements are substantially evenly circumferentially spaced about the outer surface of the roller.

40. The combination of claim 35,

wherein the antenna includes a pair of antenna elements;

and

wherein each of the antenna elements is capacitively coupled to respective of the coupling elements.

41. In combination, a radio frequency identification (RFID) device and an RFID device tester, comprising:

the RFID device, which includes;

an antenna having a pair of antenna elements; and

a chip operatively coupled to the antenna; and

the RFID device tester, which includes;

a reader; and

a pair of electrically-conductive coupling elements electrically connected to

the reader;

wherein the antenna elements are each capacitively coupled with respective of the coupling elements, thereby forming a pair of capacitors.

42. The combination of claim 41,

further comprising dielectric materials;

wherein the dielectric materials are parts of the capacitors, between the coupling element and the antenna element of respective of the capacitors.

43. The combination of claim 42, wherein the dielectric materials are parts of the RFID device.

44. The combination of claim 42, wherein the dielectric materials are parts of the RFID device tester.

45. The combination of claim 42, wherein the dielectric materials are portions of a unitary dielectric layer.

46. The combination of claim 42, further comprising:

respective transmission lines electrically connecting the coupling elements to the reader; and

a resistor between the transmission lines.

47. A method of testing a radio frequency identification (RFID) device, comprising:

shifting an optimum operating frequency of the device from a natural resonant frequency to a shifted resonant frequency; and

reading the device at a frequency other than the natural resonant frequency.

48. The method of claim 47, wherein the reading includes reading the device at about the shifted resonant frequency.

49. The method of claim 47, wherein the shifting includes placing the device in close proximity to shifting elements that shift the optimum operating frequency.

50. The method of claim 49, wherein the shifting elements include dielectric elements.

51. The method of claim 50, wherein the dielectric elements include a ceramic material.

52. The method of claim 49, wherein the shifting elements include electrically-conducting elements.

53. The method of claim 49, wherein the shifting elements are parts of an RFID device tester that also performs the reading of the device.

54. The method of claim 53, wherein the reading includes capacitively coupling the tester and the device.

55. The method of claim 49, wherein the shifting elements are part of a test fixture that is separate from an RFID device tester that performs the reading of the device.

56. The method of claim 55, wherein the reading includes radio frequency coupling a reader to the device.

57. The method of claim 49,

wherein the RFID device includes an antenna with antenna elements;

and

wherein the shifting includes at least partially overlapping the antenna elements with the shifting elements.

58. The method of claim 49, wherein the shifting includes capacitively coupling the shifting elements to an antenna of the device.

59. The method of claim 49,

wherein the device a tested RFID device is on a sheet or roll with other RFID devices;

and

wherein the placing includes placing the shifting elements closer to the tested RFID device than to any of the other RFID devices.