RFID tag especially for use near conductive objects

• US 8,665,069 B2
• Filed: 10/16/2008
• Issued: 03/04/2014
• Est. Priority Date: 10/19/2007
• Status: Active Grant

• Current Assignee: Gasngo R&D Ltd.
• Original Assignee: Petratec International Ltd.
• Inventors: Weitzhandler, Shimon, Vilnai, Yoav, Levie, Ilay, Yalon, Avi
• Primary Examiner(s): Bugg, George
• Assistant Examiner(s): Dorsey, Renee
• Application Number:
  US12/738,637
• Publication Number:
  US 20100308965A1
• Time in Patent Office: 1,965 Days
• Field of Search: None
• 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; and

b) an RFID circuit functionally associated with said antenna;

wherein said antenna, said spacer material, and said shielding layer are provided with a hole therethrough large enough to allow the RFID tag to fit around a fuel inlet or refueling port of a vehicle.

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

3. The RFID tag of claim 1, wherein permittivity of said spacer material is less than 2.

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

5. The RFID tag of claim 1, wherein permittivity of said spacer material is less than 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 0.2 mm thick.

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

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

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

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

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

16. The RFID tag of claim 15, wherein at least one said non-conducting second spacer layer is impervious to water and fuel.

17. The RFID tag of claim 15, wherein said second spacer layer is between 0.1 mm and 5 mm thick.

18. The RFID tag of claim 15, wherein at least one said non-conducting second spacer layer is an adhesive layer.

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

20. The RFID tag of claim 19, wherein said shielding layer is at least partially contained within said casing.

21. The RFID tag of claim 1, wherein said antenna, said spacer material and said shielding layer are configured for the RFID tag to be secured in proximity of said fuel inlet or refueling port of said vehicle.

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

23. The RFID tag of claim 1, wherein said shielding layer and said spacer are devoid of direct attachment.

29. The RFID tag of claim 1,

wherein said shielding layer and said spacer limit the range of communication of said antenna to a distance of 60 mm between a fuel-dispensing nozzle and said vehicle fuel inlet or refueling port.

30. The RFID tag according to claim 29, wherein said spacer material comprises polymethacrylimide foam.

31. The RFID tag of claim 1, further comprising a flexible casing substantially containing said antenna and said spacer, and said shielding layer and acting as a spacing layer between said shielding layer and said conductive material, and wherein said spacer and said shielding layer are not secured or attached to each other.

32. The RFID tag of claim 1, wherein said antenna forms a loop around said hole.

33. The RFID tag of claim 1, wherein said RFID circuit is on an opposite side of said shielding layer from said antenna, and wherein said shielding layer is secured to said conductive surface by a strong adhesive.

24. A method of identifying a vehicle, the method comprising:

a) providing 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; and

b) an RFID circuit functionally associated with said antenna;

wherein said antenna, said spacer material, and said shielding layer are provided with a hole therethrough large enough to allow said RFID tag to fit around a fuel inlet or refueling port of the vehicle;

b) securing over said fuel inlet or refueling port of the vehicle said RFID tag so that said shielding layer is located between said antenna and the vehicle, and so that said fuel inlet or refueling port is accessible through said hole;

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

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

e) receiving said transmitted identification data.

25. The method of claim 24, wherein said antenna is located in proximity of said fuel inlet or refueling port of the vehicle and said identification tag reader is functionally associated with a fuel dispensing nozzle.

26. The method of claim 25, wherein said RFID tag is secured to the vehicle so that said fuel inlet or refueling port is accessible through a loop of said antenna.

27. The method of claim 25, wherein said identification tag reader is mounted on said fuel-dispensing nozzle.

28. The method of claim 24, further comprising:

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