RFID TAG ESPECIALLY FOR USE NEAR CONDUCTIVE OBJECTS

• US 20100308965A1
• Filed: 10/16/2008
• Published: 12/09/2010
• Est. Priority Date: 10/19/2007
• Status: Active Grant

• Current Assignee: Gasngo R&D Ltd.
• Original Assignee: Petratec International Ltd.
• Inventors: Weitzhandler, Shimon, Yalon, Avi, Vilnai, Yoav, Levie, Ilay
• Granted Patent: US 8,665,069 B2
• Time in Patent Office: Days
• US Class Current: 340/10.1
• CPC Class Codes: B60K 15/04 Tank inlets B60K15/077 takes precedence
• CPC Class Codes: B67D 7/348 by interrogating an information transmitter, e.g. a transponder B67D7/145 takes precedence
• 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

An RFID tag comprising an antenna assembly, including a shielding layer comprising an electromagnetic shielding material, a radio frequency loop antenna, and a spacer comprising a spacer material having a permittivity less than about 2 interposed between the antenna and the shielding layer is disclosed. Also disclosed are methods of manufacturing such an RFID tag. Also disclosed is the use of such an RFID tag for use in identifying a vehicle, for example in the context of fuel-purchase authorization.

Claims

1. An RFID tag comprising:

a) an antenna assembly, including;

i) a shielding layer comprising an electromagnetic shielding material having a first side and a second side, said shielding layer configured to substantially reduce the magnitude of eddy currents induced in a conductive material by a magnetic field passing through said shielding layer;

ii) a radio frequency loop antenna with a loop plane located at a distance from said first side of said shielding layer; and

iii) a spacer comprising a spacer material interposed between said antenna and said shielding layer, said spacer material surrounding said antenna from the sides and having a permittivity (ε

) less than about 2; and

b) an RFID circuit functionally associated with said antenna.

2. The RFID tag of claim 1, wherein said distance is between about 0.5 mm and about 5 mm.

3. The RFID tag of claim 1, wherein said permittivity of said spacer material is less than about 1.5.

4. The RFID tag of claim 1, wherein said permittivity of said spacer material is less than about 1.3.

5. The RFID tag of claim 1, wherein said permittivity of said spacer material is less than about 1.1.

6. The RFID tag of claim 1, wherein said spacer material comprises polymethacrylimide foam.

7. The RFID tag of claim 1, wherein said shielding layer is at least about 0.2 mm thick.

8. The RFID tag of claim 1, wherein said shielding layer is no more than about 5 mm thick.

9. The RFID tag of claim 1, wherein said electromagnetic shield material comprises ferrite.

10. The RFID tag of claim 1, wherein said antenna is encased in an antenna casing associated with said spacer material.

11. The RFID tag of claim 1, wherein said antenna is sandwiched between said spacer material and a cover layer of spacer material.

13. The RFID tag of claim 1, wherein said antenna is deposited on a surface of said spacer material.

14. The RFID tag of claim 1, wherein said circuit is at least partially contained within said shielding layer.

15. The RFID tag of claim 1, wherein said circuit is at least partially contained within said spacer material.

16. The RFID tag of claim 1, further comprising at least one non-conducting second spacer layer on said second side of said shielding layer.

17. The RFID tag of claim 16, wherein at least one said non-conducting second spacer layer is impervious to water and fuel.

18. The RFID tag of claim 16, wherein said second spacer layer is between 0.1 mm and 5 mm thick.

19. The RFID tag of claim 16, wherein at least one said non-conducting second spacer layer is an adhesive layer.

20. The RFID tag of claim 1, further comprising a casing substantially containing said antenna and said spacer.

21. The RFID tag of claim 20, wherein said shielding layer is at least partially contained within said casing.

22. The RFID tag of claim 1, wherein said antenna, said spacer material and said shielding layer are provided with a hole therethrough allowing the RFID tag to fit over an object.

25. The RFID tag of claim 1, wherein said antenna and said spacer are devoid of direct attachment.

46. A method of identifying a vehicle comprising:

a) securing to said vehicle an RFID tag of claim 1 so that said shielding layer is located between said antenna and said vehicle;

b) placing an identification tag reader in proximity of said antenna;

c) activating said identification tag reader to provide power to said RFID circuit through said antenna so that said RFID circuit transmits identification data; and

d) receiving said transmitted identification data.

47. The method of claim 46, wherein said antenna is located in proximity of a refueling port of said vehicle and said identification tag reader is functionally associated with a fuel dispensing nozzle.

48. The method of claim 47, wherein said RFID tag is secured to said vehicle so that said refueling port is accessible through a loop of said antenna.

49. The method of claim 46, said identification tag reader mounted on a said fuel-dispensing nozzle.

50. The method of claim 46, further comprising:

e) based on said received identification data, optionally dispensing fuel to said vehicle.

51. The method of claim 46, wherein securing to said vehicle an RFID tag comprises securing the RFID tag over a fuel inlet of said vehicle.

12. (canceled)

23-24. -24. (canceled)

26. (canceled)

27. The RFID tag of claim 26, wherein said shielding layer and said spacer are devoid of direct attachment.

28-45. -45. (canceled)

52. An RFID tag for a vehicle comprising:

a) an antenna assembly, including;

i) a shielding layer comprising an electromagnetic shielding material having a first side and a second side, said shielding layer configured to substantially reduce the magnitude of eddy currents induced in a conductive material by a magnetic field passing through said shielding layer;

ii) a radio frequency loop antenna with a loop plane located at a distance from said first side of said shielding layer; and

iii) a spacer comprising a spacer material interposed between said antenna and said shielding layer, said spacer material having a permittivity (ε

) less than about 2; and

b) an RFID circuit functionally associated with said antenna,

wherein said shielding layer and said spacer limit the range of communication of said antenna to the typical distance between a fuel-dispensing nozzle and a vehicle refueling port.

53. An RFID tag according to claim 52, wherein said shielding layer and said spacer limit the range of communication of said antenna to about 60 mm.

54. An RFID tag according to claim 52, wherein said spacer material comprises polymethacrylimide foam.

55. An RFID tag according to claim 52, wherein said antenna, said spacer material and said shielding layer are provided with a hole therethrough allowing the RFID tag to fit over an object.

56. An RFID tag according to claim 52 wherein said object comprises a fuel inlet of the vehicle.