Capacitively powered portable communication device and associated exciter/reader and related method

• US 6,611,199 B1
• Filed: 04/16/1998
• Issued: 08/26/2003
• Est. Priority Date: 10/11/1995
• Status: Expired due to Term

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Rolin, John H., Geiszler, Theodore D., Vega, Victor Allen, Kakkanad, Sebastian Thomas, Lauro, George L., Fort, Larry W., Fletcher, Richard R., Eberhardt, Noel H., Walker, Russel E.
• Primary Examiner(s): Zimmerman, B
• Application Number:
  US09/061,146
• Time in Patent Office: 1,958 Days
• Field of Search: 340/10.51, 340/10.34, 340/572.7, 340/572.8, 340/693.5, 235/492, 342/42, 342/45, 343/841
• US Class Current: 340/10.51
• CPC Class Codes: G06K 19/0701 at least one of the integrated circuit chips comprising an arrangement for power management
• 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
• CPC Class Codes: G06Q 30/02 Marketing; Price estimation or determination; Fundraising
• CPC Class Codes: G08B 13/2417 having a radio frequency identification chip

Abstract

A portable communication device uses a first electrostatic antenna element and a second electrostatic antenna element and circuitry which is coupled to the first antenna element and to the second antenna element and which derives operating power from an electrostatic field in the vicinity of the first and second antenna elements. The electrostatic field may be provided by an array of exciter elements containing both horizontal and vertical exciter elements so that at some point as a communication device is moved across the exciter antenna array, the device will have sufficient power coupled to it to power up and become operational.

Claims

1. A method for constructing a portable identification device which, when operable, capacitively couples to a second device, the method comprising the steps of:

providing an electrically insulating carrier;

placing on the electrically insulating carrier an antenna element;

securing a circuit, which comprises first and second terminals, to the electrically insulating carrier; and

electrically coupling the first terminal to the antenna element; and

electrically coupling the second terminal to an external ground potential.

2. The method of claim 1 wherein the steps of securing and electrically coupling the first terminal involve using a conductive adhesive to secure the circuit to the electrically insulating carrier and to electrically couple the first terminal to the antenna element.

3. The method of claim 1 wherein the step of placing involves depositing a layer of conductive material onto the electrically insulating carrier.

4. The method of claim 1 wherein the second terminal is electrically coupled to the external ground potential via a second antenna element.

5. A capacitively coupled data communication system comprising:

a portable communication device comprising;

a circuit coupled to an external ground potential; and

an antenna element electrically coupled to the circuit;

an exciter device comprising;

an exciter circuit which produces an excitation signal that powers up the portable communication device;

an exciter antenna element coupled to the exciter circuit and capacitively coupled to the antenna element of the portable communication device;

a receiver antenna element capacitively coupled to the antenna element of the portable communication device, and which receives data signals transmitted by the portable communication device; and

a receiver circuit which is coupled to receive data signals received from the receiver antenna element.

6. A capacitively coupled data communication system comprising:

a portable communication device comprising;

a circuit; and

a first antenna element and a second antenna element each of which is electrically coupled to the circuit and each of which is isolated from the other;

an exciter device comprising;

an exciter circuit which produces at least one excitation signal that powers up the portable communication device;

an antenna array which includes exciter antenna elements;

a receiver antenna element which receives data signals transmitted by the portable communication device;

a receiver circuit which is coupled to receive data signals received from the receiver antenna element;

a control circuit which selectively connects at least one exciter antenna element of the antenna array to the exciter circuit; and

a plurality of sensors disposed adjacent to the array of exciter antenna elements, the plurality of sensors arranged to detect the presence and direction of motion of the portable communication device, wherein the control circuit is further arranged to selectively connect one or more exciter antenna elements of the array based upon the portable communication device motion sensed by at least one of the plurality of sensors.

7. A capacitively coupled data communication system comprising:

a portable communication device comprising;

a circuit; and

a first antenna element and a second antenna element each of which is electrically coupled to the circuit and each of which is isolated from the other;

an exciter device comprising;

an exciter circuit which produces at least one excitation signal that powers up the portable communication device;

an antenna array which includes exciter antenna elements;

a receiver antenna element which receives data signals transmitted by the portable communication device;

a receiver circuit which is coupled to receive data signals received from the receiver antenna element; and

a control circuit which selectively connects at least one exciter antenna element of the antenna array to the exciter circuit,

wherein multiple sensor elements are disposed about a periphery of the array of exciter antenna elements, the multiple sensor elements arranged to detect the presence and direction of motion of the portable communication device.

8. A portable communication device which, when operable, capacitively couples to a second device, the portable communication device comprising:

a circuit operably coupled to an external ground potential; and

an antenna element electrically coupled to the circuit.

9. The portable communication device of claim 8 further comprising:

a substrate, wherein the antenna element is formed on the substrate, and wherein the circuit is secured to the substrate.

10. The portable communication device of claim 9 wherein the substrate is selected from a group consisting of:

paper, acetate, molar, polyester, polyethylene, polypropylene, polypropylene with calcium carbonate, plastic, electrically insulating tape.

11. The portable communication device of claim 9 wherein the substrate is paper and the antenna element is formed of conductive ink.

12. The portable communication device of claim 9 wherein the substrate is acetate and the antenna element is formed of conductive ink.

13. The portable communication device of claim 9 wherein the substrate is paper and the antenna element is a conductive material.

14. The portable communication device of claim 9 wherein the substrate is plastic and the antenna element is a conductive material.

15. The portable communication device of claim 9 further comprising a conductive adhesive that secures the circuit to the substrate and that electrically couples the circuit to the antenna element.

16. The portable communication device of claim 8 wherein the circuit further comprises:

circuitry for receiving energy from the antenna element;

a memory comprising stored information; and

a circuit powered by the circuitry that generates a frequency that is modulated as a function of the stored information.

17. The portable communication device of claim 8 wherein the circuit further comprises:

a memory having stored digital information; and

a signal generator arranged for generating a carrier signal that is modulated based on the stored digital information.

18. The portable communication device of claim 17 wherein the signal generator is electrically coupled to the antenna element.

19. The portable communication device of claim 17 further comprising a second antenna element electrically coupled to the signal generator so as to transmit digital signals produced by the signal generator.

20. The portable communication device of claim 8 wherein the circuit is operably coupled to the external ground potential via a second antenna element.

21. The portable communication device of claim 8 wherein the circuit derives operating power from an electrostatic field in the vicinity of the antenna element.

22. A portable communication device which becomes operable when electrostatically coupled to a second device, the portable communication device comprising:

a circuit coupled to an external ground potential; and

at least a first antenna element electrically coupled to the circuit.

23. A capacitively coupled data communication system comprising:

a portable communication device comprising;

a circuit; and

a first antenna element and a second antenna element each of which is electrically coupled to the circuit and each of which is isolated from the other;

an exciter device comprising;

an exciter circuit which produces at least one excitation signal that powers up the portable communication device;

an antenna array which comprises exciter antenna elements, wherein the exciter antenna elements are excited in a dynamically changing pattern; and

a control circuit which selectively connects at least one exciter antenna element of the antenna array to the exciter circuit.

24. A method comprising the steps of:

at a first device;

providing a first antenna element;

generating an electric voltage signal on the first antenna element; and

transmitting an electric field signal via the first antenna element and an external ground potential; and

at a second device;

providing a device antenna element and a circuit, wherein the circuit is coupled to the external ground potential; and

receiving energy from the electric field via the device antenna element.

25. The method of claim 24 wherein the step of transmitting further comprises the step of generating a carrier signal having a frequency with a range of 25 Hz to 40 MHz.

26. The method of claim 24 wherein the external ground potential is an earth ground.

28. The method of claim 24 further comprising the step of transmitting data via the device antenna element.

30. A device comprising:

an exciter circuit coupled to an external ground potential, wherein the exciter circuit produces an electrostatic excitation signal that capacitively powers a second device;

an exciter antenna element coupled to the exciter circuit;

a receiver circuit coupled to the external ground potential, wherein the receiver circuit capacitively couples to the second device to receive data signals transmitted from the second device; and

a receiver antenna element coupled to the receiver circuit.

27. The method of claim 38 further comprising the step of orienting the second device such that the device antenna element receives the electric field signal.

29. The method of claim 27 wherein the step of orienting involves positioning the second device a distance away from the first device in a range from 0.2 mm to 50 M.

31. The device of claim 30 wherein the second device is coupled to the external ground potential.

32. The device of claim 30 further comprising a detector, coupled to the receiver circuit, for detecting data from the data signals transmitted from the second device.

33. The device of claim 32 further comprising a processor, coupled to the detector, for formatting the data.

38. The device of claim 32 wherein the circuit is operably coupled to the external ground potential via a second antenna element.

39. The device of claim 38 wherein the second antenna element has a second dimension, and the second dimension of the second antenna element is independent of the wavelength of the excitation signal.

34. A portable communication device comprising:

a first antenna element and a second antenna element; and

a circuit coupled to the first antenna element, the second antenna element and an external ground potential, and which derives a supply voltage from a voltage difference between the first antenna element and the external ground potential, and which transmits signals over the second antenna element.

35. The device of claim 34 wherein the circuit is operably coupled to the external ground potential via a third antenna element.

36. The device of claim 34 further comprising a substrate on which the first and second antenna elements are disposed and which provides electrical isolation between the first and second antenna elements and the external ground potential.

37. A remotely powered device comprising:

an antenna element having a dimension; and

a circuit coupled to the antenna element and an external ground potential, for receiving energy from an excitation signal having a wavelength via the antenna element,

wherein the dimension of the antenna element is independent of the wavelength of the excitation signal.

40. A capacitively coupled system comprising:

an exciter device comprising;

an exciter circuit coupled to an external ground potential;

an exciter antenna element coupled to the exciter circuit;

a receiver circuit coupled to the external ground potential;

a receiver antenna element coupled to the receiver circuit; and

a remotely powered device comprising;

a device antenna element capacitively coupled to the exciter antenna element and the receiver antenna element; and

a circuit couples to the device antenna element and to the external ground potential.

41. The system of claim 40 wherein the circuit couples to the external ground potential via a second device antenna.

42. The system of claim 41 wherein he antenna element has a different conductivity than the second antenna element.

43. The system of claim 41 wherein the antenna element is constructed of a material different than the second antenna element.

44. The system of claim 40 wherein the device antenna element transmits and receives data signals.

45. The system of claim 40 wherein the external ground potential is an earth ground.

46. The system of claim 40 wherein the device antenna element receives at least one of data and power.

53. The device of claim 44 wherein the circuit further comprises a rectifier coupled to the antenna element.

54. The device of claim 53 wherein the circuit further comprises an energy storage device coupled to the rectifier.

47. A device comprising:

an antenna element; and

a circuit coupled to the antenna element and operably coupled to an external ground potential,

wherein the circuit accepts energy received by the antenna element, and

wherein the antenna element is not required to be resonant with respect to a frequency.

48. The device of claim 47 further comprising a substrate, wherein the antenna element and the circuit are disposed on the substrate.

49. The device of claim 48 wherein the substrate is a non-conductive material.

50. The device of claim 48 wherein at least a portion of the substrate is covered by a layer of adhesive.

51. The device of claim 50 wherein the adhesive is selected from a group consisting of an anisotropic conductive adhesive, and an isotropic conductive adhesive.

52. The device of claim 48 further comprising an adhesive that secures the circuit to the substrate.

55. The device of claim 47 wherein the antenna element is electrically isolated from the external ground potential.

56. The device of claim 47 wherein the circuit optimizes an impedance between the antenna element and the external ground potential so as to increase a range of operation for the device.

57. The device of claim 47 wherein the circuit optimizes an impedance between the antenna element and the external ground potential so as to decrease a range of operation for the device.

58. The device of claim 47 wherein the circuit further comprises a modulator coupled to the antenna element.

59. The device of claim 47 wherein the circuit further comprises a memory for storing information.

60. The device of claim 47 wherein the circuit further comprises a counter coupled to the antenna element, for generating timing signals.

61. The device of claim 47 wherein the antenna element is substantially non-metallic.

62. The device of claim 47 wherein the antenna element is quasi-conductive.

63. The device of claim 47 wherein the circuit is operably coupled to the external ground potential via a second antenna element.

64. The device of claim 49 therein the antenna element is conductive.