RFID tags

• US 7,205,898 B2
• Filed: 09/30/2005
• Issued: 04/17/2007
• Est. Priority Date: 10/04/2004
• Status: Expired due to Fees

• Current Assignee: Laird Technologies Incorporated (DuPont de Nemours, Inc.)
• Original Assignee: Emerson & Cuming Microwave Products, Inc. (DuPont de Nemours, Inc.)
• Inventors: Osward, Mary M., Carpenter, Michael P., Gibbs, David A., Dixon, Paul F.
• Primary Examiner(s): Wu; Daniel
• Assistant Examiner(s): Bugg; George A.
• Application Number:
  US11/239,996
• Publication Number:
  US 20060109124A1
• Time in Patent Office: 564 Days
• Field of Search: 340/572.1
• US Class Current: 340/572.1
• 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 19/07771 the record carrier comprising means for minimising adverse effects on the data communication capability of the record carrier, e.g. minimising Eddy currents induced in a proximate metal or otherwise electromagnetically interfering object

Abstract

A system and method for the use of ultra high frequency RFID tags in conjunction with metal substrates, as well as substrates used to contain liquid. Briefly, an RFID isolator comprised of a material with complex magnetic permeability, used either by itself, or in combination with dielectric isolator material, is interposed between the RFID tag and the substrate. Alternatively, a material possessing at least two distinct dielectric constants is interposed between the RFID tag and the substrate, such that there is a high dielectric constant at the interface with the substrate, and a low dielectric constant at the interface with the RFID tag. This material can be a single material having a dielectric constant gradient, or alternatively, two or more separate layers, each with a uniform but different dielectric constant, sandwiched together.

Claims

1. An identification system, adapted to transmit identifying information about an article via radio frequency, comprising:

an RFID tag, adapted to transmit said identifying information via radio frequency when energized;

a first layer having first and second opposite surfaces and a first dielectric constant, wherein said first surface is adapted to be in contact with said article;

a second layer having first and second opposite surfaces and a second dielectric constant, wherein said second surface of said second layer is in contact with said RFID tag, wherein said first and said second dielectric constants are unequal.

2. The system of claim 1, wherein said first dielectric constant is greater than said second dielectric constant.

3. The system of claim 1, wherein said first layer comprises titanium dioxide.

4. The system of claim 1, wherein said second layer comprises titanium dioxide.

5. The system of claim 1, wherein said first surface of said second layer is in contact with a second surface of said first layer.

6. The system of claim 1, wherein said first layer has permeability greater than one.

7. The system of claim 1, wherein said first dielectric constant is from about 9 to about 30.

8. The system of claim 1, wherein said second dielectric constant is from about 2 to about 10.

9. The system of claim 1, further comprising a third layer, having a third dielectric constant whose value is greater than said second dielectric constant and less than said first dielectric constant, wherein said third layer is interposed between said second surface of said first layer and said first surface of said second layer.

10. An identification system, adapted to transmit identifying information about an article via radio frequency, comprising:

an RFID tag, adapted to transmit said identifying information via radio frequency when energized;

and a first layer having first and second opposite surfaces, a dielectric constant, and a magnetic permeability greater than 1, wherein said first layer is interposed between said article and said RFID tag.

11. The system of claim 10, wherein said first layer is comprised of carbonyl iron, nickel-zinc ferrite or magnetite.

12. The system of claim 10, wherein said magnetic permeability is from about 1.5 to about 7.

13. The system of claim 10, wherein said dielectric constant is from about 4 to about 32.

14. The system of claim 10, wherein said first surface of said first layer is in contact with said article and said second surface of said first layer is in contact with said RFID tag.

15. The system of claim 10, further comprising a second layer having first and second opposite surfaces, interposed between said first layer and said RFID tag.

16. The system of claim 15, wherein said second layer has a dielectric constant from about 1.5 to about 10.

17. The system of claim 15, wherein said second layer has a magnetic permeability greater than 1.

18. The system of claim 17, wherein said second layer has a magnetic permeability less than the permeability of said first layer.

19. The system of claim 15, wherein said first surface of said first layer is in contact with said article, said second surface of said first layer is in contact with said first surface of said second layer and said second surface of said second layer is in contact with said RFID tag.

20. An identification system, adapted to transmit identifying information about an article via radio frequency, comprising:

an RFID tag, adapted to transmit said identifying information via radio frequency when energized; and

a layer, having a first surface adapted to be in contact with said article, and a second opposite surface in contact with said RFID tag, wherein said layer has a dielectric constant gradient between said first surface and said second surface.

21. The system of claim 20, wherein said dielectric constant at said first surface is greater than the dielectric constant at said second surface.

22. A radio frequency identification system, adapted to transmit identifying information about an article comprising;

a substrate comprising an integrated circuit containing said identifying information and an antenna adapted to transmit said identifying information;

a first layer, having first and second opposite surfaces and a first dielectric constant, wherein said first surface is adapted to be in contact with said article; and

a second layer, having first and second opposite surfaces and a second dielectric constant, wherein said second surface of said second layer is in contact with said substrate and said first and second dielectric constants are unequal.

23. The system of claim 22, wherein said first dielectric constant is greater than said second dielectric constant.

24. The system of claim 22, wherein said first layer comprises titanium dioxide.

25. The system of claim 22, wherein said second layer comprises titanium dioxide.

26. The system of claim 22, wherein said first surface of said second layer is in contact with a second surface of said first layer.

27. The system of claim 22, wherein said first layer has permeability greater than one.

28. The system of claim 22, wherein said first dielectric constant is from about 9 to about 30.

29. The system of claim 22, wherein said second dielectric constant is from about 2 to about 10.

30. The system of claim 22, further comprising a third layer, having a third dielectric constant whose value is greater than said second dielectric constant and less than said first dielectric constant, wherein said third layer is interposed between said second surface of said first layer and said first surface of said second layer.

31. The system of claim 22, wherein said substrate further comprises a first surface upon which said integrated circuit and said antenna are located and a second surface in contact with said second surface of said second layer.

32. A radio frequency identification system, adapted to transmit identifying information about an article comprising;

a substrate comprising an integrated circuit containing said identifying information and an antenna adapted to transmit said identifying information;

and a first layer, having first and second opposite surfaces, a dielectric constant, and a magnetic permeability greater than 1, wherein said first layer is interposed between said article and said RFID tag.

33. The system of claim 32, wherein said first layer is comprised of carbonyl iron, nickel-zinc ferrite or magnetite.

34. The system of claim 32, wherein said magnetic permeability is from about 1.5 to about 7.

35. The system of claim 32, wherein said dielectric constant is from about 4 to about 32.

36. The system of claim 32, wherein said first surface of said first layer is in contact with said article and said second surface of said first layer is in contact with said RFID tag.

37. The system of claim 32, further comprising a second layer having first and second opposite surfaces, interposed between said first layer and said substrate.

38. The system of claim 37, wherein said second layer has a dielectric constant from about 1.5 to about 10.

39. The system of claim 37, wherein said second layer has a magnetic permeability greater than 1.

40. The system of claim 39, wherein said second layer has a magnetic permeability less than the permeability of said first layer.

41. The system of claim 37, wherein said first surface of said first layer is in contact with said article, said second surface of said first layer is in contact with said first surface of said second layer and said second surface of said second layer is in contact with said substrate.

42. A radio frequency identification system, adapted to transmit identifying information about an article comprising;

a substrate comprising an integrated circuit containing said identifying information and an antenna adapted to transmit said identifying information; and

a layer, having first and second opposite surfaces interposed between said substrate and said article adapted to be in contact with said article, wherein said layer has a dielectric constant gradient between said first surface and said second surface.

43. The system of claim 42, wherein the dielectric constant at said first surface is greater than the dielectric constant at said second surface.

44. The system of claim 42, wherein said substrate further comprises a first surface upon which said integrated circuit and said antenna are located and a second surface in contact with said second surface of said layer.

45. A device, comprising:

an article having a surface;

a first layer in contact with said surface of said article, having first and second opposite surfaces and having a first dielectric constant;

a second layer having first and second opposite surfaces and having a second dielectric constant different from said first dielectric constant; and

an RFID tag in contact with said second layer, said RFID tag adapted to transmit identifying information about said article via radio frequency when energized.

46. The device of claim 45, wherein said first dielectric constant is greater than said second dielectric constant.

47. The device of claim 45, wherein said first layer comprises titanium dioxide.

48. The device of claim 45, wherein said second layer comprises titanium dioxide.

49. The device of claim 45, wherein said first surface of said second layer is in contact with a second surface of said first layer.

50. The device of claim 45, wherein said first layer has permeability greater than one.

51. The device of claim 45, wherein said first dielectric constant is from about 9 to about 30.

52. The device of claim 45, wherein said second dielectric constant is from about 2 to about 10.

53. The device of claim 45, further comprising a third layer, having a third dielectric constant whose value is greater than said second dielectric constant and less than said first dielectric constant, wherein said third layer is interposed between said second surface of said first layer and said first surface of said second layer.

54. The device of claim 45, wherein said substrate further comprises a first surface upon which said integrated circuit and said antenna are located and a second surface in contact with said second surface of said second layer.

55. The device of claim 45, wherein said surface of said article comprises metal.

56. The device of claim 45, wherein said article contains liquid.

57. A device, comprising:

an article having a surface;

an RFID tag adapted to transmit identifying information about said article via radio frequency when energized; and

a first layer having first and second opposite surfaces, a dielectric constant and a magnetic permeability greater than 1, wherein said first layer is interposed between said article and said RFID tag.

58. The device of claim 57, wherein said first layer is comprised of carbonyl iron, nickel-zinc ferrite or magnetite.

59. The device of claim 57, wherein said magnetic permeability is from about 1.5 to about 7.

60. The device of claim 57, wherein said dielectric constant is from about 4 to about 32.

61. The device of claim 57, wherein said first surface of said first layer is in contact with said article and said second surface of said first layer is in contact with said RFID tag.

62. The device of claim 57, further comprising a second layer having first and second opposite surfaces, interposed between said first layer and said RFID tag.

63. The device of claim 62, wherein said second layer has a dielectric constant from about 1.5 to about 10.

64. The device of claim 62, wherein said second layer has a magnetic permeability greater than 1.

65. The device of claim 64, wherein said second layer has a magnetic permeability less than the permeability of said first layer.

66. The device of claim 62, wherein said first surface of said first layer is in contact with said article, said second surface of said first layer is in contact with said first surface of said second layer and said second surface of said second layer is in contact with said RFID tag.

67. The device of claim 57, wherein said surface of said article comprises metal.

68. The device of claim 57, wherein said article contains liquid.

69. A device, comprising:

an article having a surface;

a first layer in contact with said surface of said article, having first and second opposite surfaces;

an RFID tag in contact with said layer, said RFID tag adapted to transmit identifying information about said article via radio frequency when energized;

wherein said layer has a dielectric gradient such that the dielectric constant at the interface of said layer and said surface is different from the dielectric constant at the interface of said layer and said RFID tag.

70. The device of claim 69, wherein said dielectric at the interface of said layer and said surface is greater than the dielectric constant at the interface of said layer and said RFID tag.

71. The device of claim 69, wherein said surface of said article comprises metal.

72. The device of claim 69, wherein said article contains liquid.