Method and apparatus for testing RFID tags

• US 6,104,291 A
• Filed: 10/06/1998
• Issued: 08/15/2000
• Est. Priority Date: 01/09/1998
• Status: Expired due to Term

• Current Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Original Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Inventors: Beauvillier, Luc, Friedman, Daniel J., Duan, Dah-Weih, Murphy, Philip, Brady, Michael John, Moskowitz, Paul Andrew
• Primary Examiner(s): SWANN III, GLEN R
• Application Number:
  US09/167,026
• Time in Patent Office: 679 Days
• Field of Search: 340/572.1, 340/572.5
• US Class Current: 340/572.1
• CPC Class Codes: G01R 31/2822 of microwave or radiofrequency circuits of attenuation, gain, e.g. using network analyzers G01R27/28
• 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 7/0095 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 7/10079 the collision being resolved in the spatial domain, e.g. temporary shields for blindfolding the interrogator in specific directions
• CPC Class Codes: G08B 13/2408 using ferromagnetic tags
• CPC Class Codes: G08B 13/2417 having a radio frequency identification chip
• CPC Class Codes: G08B 13/244 Tag manufacturing, e.g. continuous manufacturing processes

Abstract

The present invention provides a method and apparatus for testing RFID tags using wireless radio frequency (RF) communication. The method and apparatus allow RFID tags to be tested individually or in groups while they are in close proximity to each other (e.g., within the read range of the tag).

Claims

1. An apparatus for testing RFID tags using wireless radio frequency communication, comprising:

a test assembly generating a radio frequency field for communicating with an RFID tag when the RFID tag is positioned within the radio frequency field; and

a carriage for sequentially positioning RFID tags within the radio frequency field generated by said test assembly.

2. The apparatus of claim 1, further comprising an RF shield for shielding RFID tags from the radio frequency field until they are positioned therein by said carriage.

3. The apparatus of claim 2, wherein said RF shield comprises a chamber enclosing said test assembly.

4. The apparatus of claim 3, wherein said carriage positions RFID tags within said chamber.

5. The apparatus of claim 4, wherein said carriage positions RFID tags within a region of exposure to the radio frequency field.

6. The apparatus of claim 3, wherein the chamber comprises an anechoic chamber.

7. The apparatus of claim 3, wherein said test assembly comprises a radio frequency transceiver for generating the radio frequency field and processing return signals from the RFID tag.

8. The apparatus of claim 7, wherein said test assembly further comprises an antenna disposed within said chamber and operatively coupled to said transceiver for propagating the RF field.

9. The apparatus of claim 8, wherein said antenna also receives return signals from the RFID tag.

10. The apparatus of claim 3, wherein said test assembly comprises a radio frequency transmitter and receiver for generating the radio frequency field and processing return signals from the RFID tag.

11. The apparatus of claim 10, wherein said test assembly further comprises an antenna disposed within said chamber and operatively coupled to said transceiver for propagating the RF field.

12. The apparatus of claim 11, wherein said antenna also receives return signals from the RFID tag.

13. The apparatus of claim 3, wherein the chamber comprises a resonant cavity.

14. The apparatus of claim 13, further comprising a probe for exciting the resonant cavity by coupling RF power to the field within the resonant cavity.

15. The apparatus of claim 3, wherein said carriage comprises a rotatable stage for transporting the RFID tag into said chamber so that the RFID tag is positioned within the radio frequency field generated by said test assembly.

16. The apparatus of claim 3, wherein said carriage comprises a conveyor for transporting the RFID tag into said chamber so that the RFID tag is positioned within the radio frequency field generated by said test assembly.

17. The apparatus of claim 2, wherein said RF shield is positioned between said carriage and said test assembly for shielding RFID tags carried by said carriage from the radio frequency field, said RF shield including an aperture for exposing an RFID tag to the radio frequency field when the RFID tag is positioned within the aperture by the carriage.

18. The apparatus of claim 17, wherein said carriage positions the RFID tag within a region of exposure to the radio frequency field.

19. The apparatus of claim 17, wherein said RF shield comprises radio frequency absorbing material.

20. The apparatus of claim 17, wherein said RF shield comprises a metal plate positioned to modify the input impedance of the RFID tags.

21. The apparatus of claim 17, wherein said test assembly comprises a radio frequency transceiver for generating the radio frequency field and processing return signals from the RFID tag.

22. The apparatus of claim 21, wherein said test assembly further comprises an antenna operatively coupled to said transceiver for propagating the RF field.

23. The apparatus of claim 22, wherein said antenna also receives return signals from the RFID tag.

24. The apparatus of claim 17, wherein said test assembly comprises a radio frequency transmitter and receiver for generating the radio frequency field and processing return signals from the RFID tag.

25. The apparatus of claim 24, wherein said test assembly further comprises an antenna operatively coupled to said transmitter and receiver for propagating the RF field.

26. The apparatus of claim 25, wherein said antenna also receives return signals from the RFID tag.

27. The apparatus of claim 17, wherein said carriage comprises a conveyor.

28. The apparatus of claim 1, wherein the volume of the RF field generated by the test assembly is substantially the same as the volume of the RFID tag, and wherein the RFID tag is positioned in proximity to the test assembly by the carriage.

29. The apparatus of claim 28, wherein said carriage positions the RFID tag within a region of exposure to the radio frequency field.

30. The apparatus of claim 28, wherein said test assembly comprises a transceiver for generating the radio frequency field and processing return signals from the RFID tag.

31. The apparatus of claim 30, wherein said test assembly comprises an antenna operatively coupled to said transceiver for propagating the radio frequency field.

32. The apparatus of claim 31, wherein said antenna also receives return signals from the RFID tag.

33. The apparatus of claim 28, wherein said carriage comprises a rotatable stage for positioning the RFID tag within the radio frequency field generated by said test assembly.

34. The apparatus of claim 28, wherein said carriage comprises a conveyor for positioning the RFID tag within the radio frequency field generated by said test assembly.

35. The apparatus of claim 1, further comprising a controller for controlling operation of the test assembly and carriage.

36. The apparatus of claim 1, further comprising a sorting apparatus for sorting tested RFID tags according to the performance of the RFID tag.

37. A method for testing RFID tags using wireless radio frequency communication, comprising the steps of:

a) generating a radio frequency field for testing the RFID tags;

b) sequentially positioning each RFID tag within the radio frequency field while substantially isolating the remaining RFID tags from the field;

b) communicating with each RFID tag while it is positioned within the radio frequency field; and

c) removing each RFID tag from the radio frequency field.

38. The method according to claim 37, wherein the positioning step comprises shielding the remaining RFID tags from the RF field.

39. The method according to claim 38, wherein the positioning step comprises transporting each RFID tag to the inside of a miniaturized anechoic chamber.

40. The method according to claim 39, wherein the positioning step comprises placing the RFID tags within the chamber in the near-field region of the radio frequency field.

41. The method according to claim 39, wherein the positioning step comprises placing each RFID tag onto a rotatable stage and rotating the stage so that the RFID tag is transported into the chamber.

42. The method according to claim 39, wherein the positioning step comprises placing each RFID tag onto a conveyor wherein the conveyor transports the RFID tag into the chamber.

43. The method according to claim 38, wherein the positioning step comprises transporting each RFID tag to the inside of a resonant cavity.

44. The method according to claim 43, wherein the positioning step comprises placing each RFID tag onto a rotatable stage and rotating the stage so that the RFID tag is transported into the resonant cavity.

45. The method according to claim 43, wherein the positioning step comprises placing each RFID tag onto a conveyor wherein the conveyor transports the RFID tag into the resonant cavity.

46. The method according to claim 38, wherein the positioning step comprises transporting the RFID tags beneath an RF shield having an aperture formed therein, and exposing each RFID tag to the radio frequency field via the aperture.

47. The method according to claim 46, wherein the positioning step comprises placing the RFID tags within the chamber in the near-field region of the radio frequency field.

48. The method according to claim 46, wherein the positioning step comprises placing each RFID tag onto a conveyor wherein the conveyor transports beneath the RF shield.

49. The method according to claim 37, wherein the positioning step comprises transporting the RFID tags near a metal object so that the RFID tags impedance matching factor is changed.

50. The method according to claim 37, wherein the positioning step comprises locating the RFID tag in an RF field having a volume substantially the same as the volume of the RFID tag wherein the intensity of the RF field applied to the RFID tag located therein is substantially greater than the intensity of the RF field applied to the remaining RFID tags.

51. The method according to claim 50, wherein the positioning step comprises placing the RFID tags within the near-field region of the radio frequency field.

52. The method according to claim 50, wherein the positioning step comprises placing each RFID tag onto a rotatable stage and rotating the stage so that the RFID tag is positioned within the radio frequency field.

53. The method according to claim 52, wherein the positioning step comprises placing each RFID tag onto a conveyor wherein the conveyor transports the RFID tag into the RF field.

54. The method according to claim 37, wherein the communicating step comprises writing information to the RFID tag.

55. The method according to claim 37, wherein the communicating step comprises testing a command of the RFID tag.

56. The method according to claim 51, further comprising tabulating the results of the test and relating test parameters to the functional performance of the RFID tag.

57. The method according to claim 52, further comprising sorting each RFID tag according to its functional performance.

58. The method according to claim 37, wherein the communicating step includes determining the operation distance of the RFID tag.