Radio frequency identification tag system using tags arranged for coupling to ground

• US 6,411,213 B1
• Filed: 02/27/1998
• Issued: 06/25/2002
• Est. Priority Date: 10/11/1995
• Status: Expired due to Fees

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Fletcher, Richard, Rolin, John H., Vega, Victor Allen, Kakkanad, Sebastian Thomas
• Primary Examiner(s): SWANN III, GLEN R
• Application Number:
  US09/031,848
• Time in Patent Office: 1,579 Days
• Field of Search: 340/573.3, 340/572.7, 340/572.6, 340/572.1, 340/539, 340/531, 340/825.54, 340/825.72, 119/720, 455/41
• US Class Current: 340/573.3
• CPC Class Codes: A01K 11/004 with electronic identification means, e.g. transponders
• 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 19/07788 the antenna being of the capacitive type
• 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 7/10069 the collision being resolved in the frequency domain, e.g. by hopping from one frequency to the other frequency hopping or spread spectrum techniques H04B7/00
• CPC Class Codes: G06K 7/10326 the antenna being of the very-near field type, e.g. capacitive

Abstract

A radio frequency identification tag system (10) utilizes a radio frequency identification tag (16) that includes stored information. The tag includes an antenna element (28) and a common electrode (26), the common electrode being coupled to ground (70). The antenna element electrostatically receives an exciter signal (30) from a proximately-located exciter (12). Upon receiving the exciter signal, the tag becomes energized, thereby causing it to generate a read signal (32) based on the stored information. The antenna element then electrostatically sends the read signal to a proximately-located reader (14), which detects the stored information. Both energy and data are capacitively coupled by virtue of the unbalanced nature of the network, thus resulting in decreased coupled impedance.

Claims

1. A radio frequency identification tag comprising:

a tag circuit, a tag common electrode and a tag antenna element,

the tag common electrode and the tag antenna element coupled to the tag circuit,

the tag common electrode arranged for coupling to ground;

the tag antenna element arranged for electrostatically receiving an exciter signal and coupling the exciter signal to the tag circuit;

the tag circuit arranged for becoming energized based on the exciter signal, generating a read signal and coupling the read signal to the tag antenna element; and

the tag antenna element arranged for electrostatically transmitting the read signal.

2. The radio frequency identification tag of claim 1, wherein the read signal is a reflected signal.

3. The radio frequency identification tag of claim 1, wherein the tag common electrode is arranged for coupling to an article.

4. The radio frequency identification tag of claim 3, wherein the tag common electrode is arranged for coupling to ground by means of the article.

5. The radio frequency identification tag of claim 1, wherein the tag common electrode is arranged for coupling to an animal or a person.

6. The radio frequency identification tag of claim 5, wherein the tag common electrode is arranged for coupling to ground by means of one of the animal or the person.

7. The radio frequency identification tag of claim 1, wherein the tag circuit comprises stored tag information, and the read signal is based on the stored tag information.

8. The radio frequency identification tag of claim 7, wherein the tag antenna element is arranged for receiving a transmitted write signal and coupling the transmitted write signal to the tag circuit, the transmitted write signal comprising write information,

the tag circuit is arranged for storing the write information as the stored tag information, and

the read signal is modulated by means of a reflected load modulation based on the stored tag information.

9. The radio frequency identification tag of claim 8, wherein the read signal is further modulated by at least one of an amplitude modulation, a frequency modulation and a phase modulation.

10. The radio frequency identification tag of claim 8, wherein the write information comprises at least one of an operational code and a command.

11. A radio frequency identification tag comprising;

a tag circuit, a tag common electrode, a first tag antenna element and a second tag antenna element;

the tag common electrode and the first and second tag antenna elements coupled to the tag circuit;

the tag common electrode arranged for coupling to ground;

the first tag antenna element arranged for electrostatically receiving an exciter signal and coupling the exciter signal to the tag circuit;

the tag circuit arranged for becoming energized based on the exciter signal, generating a read signal and coupling the read signal to the second tag antenna element; and

the second tag antenna element arranged for electrostatically transmitting the read signal.

12. The radio frequency identification tag of claim 11, wherein the read signal is a transmitted signal.

13. The radio frequency identification tag of claim 11, wherein the tag common electrode is arranged for coupling to an article.

14. The radio frequency identification tag of claim 13, wherein the tag common electrode is arranged for coupling to ground by means of the article.

15. The radio frequency identification tag of claim 11, wherein the tag common electrode is arranged for coupling to an animal or a person.

16. The radio frequency identification tag of claim 15, wherein the tag common electrode is arranged for coupling to ground by means of one of the animal or the person.

17. The radio frequency identification tag of claim 11, wherein the tag circuit comprises stored tag information, and the read signal is based on the stored tag information.

18. The radio frequency identification tag of claim 17, wherein the first tag antenna element is arranged for receiving a transmitted write signal and coupling the transmitted write signal to the tag circuit, the transmitted write signal comprising write information,

the tag circuit is arranged for storing the write information as the stored tag information, and

the read signal is modulated based on the stored tag information.

19. The radio frequency identification tag of claim 18, wherein the read signal is further modulated by at least one of an amplitude modulation, a frequency modulation and a phase modulation.

20. The radio frequency identification tag of claim 18, wherein the write information comprises at least one of an operational code and a command.

21. An electrostatic exciter comprising:

an exciter circuit, an exciter common electrode, and an exciter antenna element,

the exciter common electrode and the exciter antenna element coupled to the exciter circuit, the exciter common electrode arranged for coupling to ground,

the exciter circuit arranged for generating an exciter signal and coupling the exciter signal to the exciter antenna element, and

the exciter antenna element arranged for electrostatically transmitting the exciter signal to a radio frequency identification tag.

22. The electrostatic exciter of claim 21, wherein the exciter circuit arranged for generating a transmitted write signal and coupling the transmitted write signal to the exciter antenna element, the transmitted write signal comprising write information, and

the exciter antenna element arranged for electrostatically transmitting the transmitted write signal.

23. A radio frequency identification tag system comprising:

an electrostatic exciter and at least one radio frequency identification tag,

the electrostatic exciter comprising an exciter circuit, an exciter common electrode and an exciter antenna element, the exciter common electrode and the exciter antenna element coupled to the exciter circuit, the exciter common electrode arranged for coupling to ground,

the exciter circuit arranged for generating an exciter signal and coupling the exciter signal to the exciter antenna element,

the exciter antenna element arranged for electrostatically sending the exciter signal to the at least one radio frequency identification tag, and

the at least one radio frequency identification tag arranged for coupling to ground.

24. The radio frequency identification tag system of claim 23, wherein the exciter circuit is arranged for generating a transmitted write signal and coupling the transmitted write signal to the exciter antenna element, the transmitted write signal comprising write information,

the exciter antenna element arranged for electrostatically sending the transmitted write signal to the at least one radio frequency identification tag, and

the at least one radio frequency identification tag arranged for storing the write information.

25. The radio frequency identification tag system of claim 23, wherein the at least one radio frequency identification tag is arranged for coupling to an article, and arranged for coupling to ground by means of the article.

26. The radio frequency identification tag system of claim 23, wherein the at least one radio frequency identification tag is arranged for coupling to an animal or a person, and arranged for coupling to ground by means of one of the animal or the person.

27. The radio frequency identification tag system of claim 23, the at least one radio frequency identification tag comprising:

a tag circuit, a tag common electrode and a tag antenna element,

the tag common electrode and the tag antenna element coupled to the tag circuit,

the tag common electrode arranged for coupling to ground;

the tag antenna element arranged for electrostatically receiving the exciter signal from the exciter antenna element and coupling the exciter signal to the tag circuit;

the tag circuit arranged for becoming energized based on the exciter signal, generating a read signal and coupling the read signal to the tag antenna element; and

the tag antenna element arranged for electrostatically transmitting the read signal.

28. The radio frequency identification tag system of claim 23, the at least one radio frequency identification tag comprising:

a tag circuit, a tag common electrode, a first tag antenna element and a second tag antenna element,

the tag common electrode, the first and second tag antenna elements coupled to the tag circuit,

the tag common electrode arranged for coupling to ground;

the first tag antenna element arranged for electrostatically receiving the exciter signal from the exciter antenna element and coupling the exciter signal to the tag circuit;

the tag circuit arranged for becoming energized based on the exciter signal, generating a read signal and coupling the read signal to the second tag antenna element; and

the second tag antenna element arranged for electrostatically transmitting the read signal.

29. An apparatus comprising:

an electrostatic exciter and an electrostatic reader,

the electrostatic exciter comprising an exciter circuit, an exciter common electrode and an exciter antenna element, the exciter common electrode and the exciter antenna element coupled to the exciter circuit, the exciter common electrode arranged for coupling to ground,

the exciter circuit arranged for generating an exciter signal and coupling the exciter signal to the exciter antenna element,

the exciter antenna element arranged for electrostatically transmitting the exciter signal to a radio frequency identification tag arranged for coupling to ground, and

the electrostatic reader comprising a reader circuit and a reader antenna element, the reader antenna element coupled to the reader circuit,

the reader antenna element arranged for electrostatically receiving a read signal from the radio frequency identification tag and coupling the read signal to the reader circuit.

30. The apparatus of claim 29, wherein the read signal is a reflected signal and is modulated by means of a reflected load modulation based on the stored tag information.

31. The apparatus of claim 30, wherein the read signal is further modulated by at least one of an amplitude modulation, a frequency modulation and a phase modulation.

32. The apparatus of claim 30, wherein the read signal is a transmitted signal and is modulated based on the stored tag information.

33. The apparatus of claim 32, wherein the read signal is further modulated by at least one of an amplitude modulation, a frequency modulation and a phase modulation.

34. The apparatus of claim 29, wherein the exciter circuit is arranged for generating a transmitted write signal and coupling the transmitted write signal to the exciter antenna element, the transmitted write signal comprising write information, and

the exciter antenna element arranged for electrostatically sending the transmitted write signal.

35. The apparatus of claim 34, the stored tag information being based on the write information.

36. A radio frequency identification tag system comprising:

an electrostatic exciter, an electrostatic reader and at least one radio frequency identification tag,

the electrostatic exciter comprising an exciter circuit, an exciter common electrode and an exciter antenna element, the exciter common electrode and the exciter antenna element coupled to the exciter circuit, the exciter common electrode arranged for coupling to ground,

the exciter circuit arranged for generating an exciter signal and coupling the exciter signal to the exciter antenna element,

the exciter antenna element arranged for electrostatically sending the exciter signal to the at least one radio frequency identification tag,

the electrostatic reader comprising a reader circuit and a reader antenna element, the reader antenna element coupled to the reader circuit,

the reader antenna element arranged for electrostatically receiving a read signal from the at least one radio frequency identification tag and coupling the read signal to the reader circuit,

the at least one radio frequency identification tag including a stored tag information,

the read signal based on the stored tag information, and

the reader circuit arranged for detecting the stored tag information.

37. The radio frequency identification tag system of claim 36, wherein the at least one radio frequency identification tag comprises:

a tag circuit, a tag common electrode and a tag antenna element,

the tag common electrode and the tag antenna element coupled to the tag circuit,

the tag common electrode arranged for coupling to ground;

the tag antenna element arranged for electrostatically receiving the exciter signal from the exciter antenna element and coupling the exciter signal to the tag circuit;

the tag circuit arranged for becoming energized based on the exciter signal, generating the read signal and coupling the read signal to the tag antenna element;

the tag antenna element arranged for electrostatically spending the read signal to the reader antenna element; and

the read signal being a reflected signal.

38. The radio frequency identification tag system of claim 37,

the exciter circuit arranged for generating a transmitted write signal and coupling the transmitted write signal to the exciter antenna element, the transmitted write signal including write information, and

the exciter antenna element arranged for electrostatically sending the transmitted write signal to the at least one radio frequency identification tag.

39. The radio frequency identification tag system of claim 38,

the tag antenna element arranged for receiving the transmitted write signal and coupling the transmitted write signal to the tag circuit,

the tag circuit arranged for storing the write information as the stored tag information, and

the read signal being modulated by means of a reflected load modulation based on the stored tag information.

40. The radio frequency identification tag system of claim 39, the read signal being further modulated by at least one of an amplitude modulation, a frequency modulation and a phase modulation.

41. The radio frequency identification tag system of claim 37, the tag common electrode arranged for coupling to an article, and arranged for coupling to ground by means of the article.

42. The radio frequency identification tag system of claim 37, the tag common electrode arranged for coupling to an animal or a person, and arranged for coupling to ground by means of one of the animal or the person.

43. The radio frequency identification tag system of claim 36, the at least one radio frequency identification tag including:

a tag circuit, a tag common electrode, a first tag antenna element and a second tag antenna element,

the tag common electrode, the first and second tag antenna elements coupled to the tag circuit,

the tag common electrode arranged for coupling to ground;

the first tag antenna element arranged for electrostatically receiving the exciter signal from the exciter antenna element and coupling the exciter signal to the tag circuit;

the tag circuit arranged for becoming energized based on the exciter signal, generating the read signal and coupling the read signal to the second tag antenna element;

the second tag antenna element arranged for electrostatically sending the read signal to the reader antenna element; and

the read signal being a transmitted signal.

44. The radio frequency identification tag system of claim 43, wherein the exciter circuit is arranged for generating a transmitted write signal and coupling the transmitted write signal to the exciter antenna element, the transmitted write signal comprising write information, and

the exciter antenna element arranged for electrostatically sending the transmitted write signal to the at least one radio frequency identification tag.

45. The radio frequency identification tag system of claim 44, wherein the first tag antenna element is arranged for receiving the transmitted write signal and coupling the transmitted write signal to the tag circuit,

the tag circuit is arranged for storing the write information as the stored tag information, and

the read signal is modulated based on the stored tag information.

46. The radio frequency identification tag system of claim 45, wherein the read signal is further modulated by at least one of an amplitude modulation, a frequency modulation and a phase modulation.

47. The radio frequency identification tag system of claim 43, wherein the tag common electrode is arranged for coupling to an article, and is arranged for coupling to ground by means of the article.

48. The radio frequency identification tag system of claim 43, wherein the tag common electrode is arranged for coupling to an animal or a person, and is arranged for coupling to ground by means of one of the animal or the person.

49. A livestock management system comprising:

a corral for holding a livestock, the corral having a sensing chute, the sensing chute comprising a first fence member and a second fence member, the first fence member being separated from the second fence member by a width to singularly direct the livestock there through;

an exciter/reader, the exciter/reader comprising an exciter antenna element and a reader antenna element, each of the exciter antenna element and the reader antenna element being formed in at least one of the first fence member and the second fence member, the exciter/reader adapted to generate an electrostatic power and data signal for transmission from the exciter antenna element and to receive an electrostatic read signal at the reader antenna element;

the livestock having a radio frequency identification tag, the radio frequency identification tag having a tag common electrode coupled to the livestock and to a tag circuit and a tag antenna element coupled to the tag circuit and insulated from the livestock, the radio frequency identification tag adapted to receive the electrostatic power and data signal from the exciter/reader and to generate aid transmit the electrostatic read signal at the tag antenna element;

the exciter/reader coupled to ground; and

within the sensing chute, the tag common electrode coupled to ground by means of the livestock.

50. The livestock management system of claim 49, wherein the radio frequency identification tag is secured in an ear of the livestock and the exciter antenna element and the reader antenna element are positioned within at least one of the first fence member and the second fence member, approximate to the ear.

51. The livestock management system of claim 49, wherein the width is slightly wider than an expected widest livestock.

52. The livestock management system of claim 49, wherein the radio frequency identification tag comprises a front plate, a post secured at a first end within an aperture formed in the front plate and at a second end to a back plate.

53. The livestock management system of claim 52, wherein the tag antenna element comprises a conductor formed within a body of the front plate.

54. The livestock management system of claim 52, wherein the tag common electrode comprises the post, the post being adapted to engage an aperture formed in an ear of the livestock and to be secured thereto by the front plate and the back plate.

55. The livestock management system of claim 52, wherein the tag circuit is formed within a body of the front plate.

56. The livestock management system of claim 52, wherein the back plate is formed from insulating plastic.

57. The livestock management system of claim 52, wherein the back plate is formed from electrically conducting plastic.