RFID tag with enhanced readability

• US 7,298,330 B2
• Filed: 11/04/2004
• Issued: 11/20/2007
• Est. Priority Date: 11/04/2003
• Status: Active Grant

• Current Assignee: Avery Dennison Retail Information Services LLC (Avery Dennison Corporation)
• Original Assignee: Avery Dennison Corporation
• Inventors: Puleston, David J., Forster, Ian J.
• Primary Examiner(s): MANCUSO, HUEDUNG XUAN CAO
• Application Number:
  US10/981,423
• Publication Number:
  US 20050093678A1
• Time in Patent Office: 1,111 Days
• Field of Search: 343/700.MS, 343/793, 343/795, 343/895, 343/879, 343866-867, 340/572.2, 340/572.4, 340/572.6, 340/572.7
• US Class Current: 343/700.0MS
• 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
• CPC Class Codes: G06K 19/07796 arrangements on the record carrier to allow stacking of a plurality of similar record carriers, e.g. to avoid interference between the non-contact communication of the plurality of record carriers
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H01Q 1/243 with built-in antennas
• CPC Class Codes: H01Q 1/273 Adaptation for carrying or wearing by persons or animals
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 13/00 Waveguide horns or mouths; Slot antennas; Leaky-waveguide antennas; Equivalent structures causing radiation along the transmission path of a guided wave
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• CPC Class Codes: H01Q 9/26 with folded element or elements, the folded parts being spaced apart a small fraction of operating wavelength resonant loop antennas H01Q7/00
• CPC Class Codes: H01Q 9/42 with folded element, the folded parts being spaced apart a small fraction of the operating wavelength

Abstract

A radio frequency identification (RFID) system includes an RFID device, and a conductive material that cooperates with the RFID device to enhance performance of the RFID device. The RFID device and the conductive material may be within a distance of about one-quarter of a wavelength of energy most preferentially received by the RFID device. The RFID device may be mounted at an angle to the conductive material. Alternatively, or in addition, the RFID device may be partially overlapped by the conductive material. The RFID device may include a conductive antenna structure having an aperture therein.

Claims

1. An RFID system comprising:

an RFID device embodied in a label or tag; and

an electrically-conductive material that is not a part of the label or tag, that cooperates with the RFID device to enhance performance of the RFID device;

wherein the RFID device has a wavelength of energy most preferentially received;

wherein at least part of an antenna structure of the RFID device is within one-quarter of the wavelength, of the conductive material; and

wherein the antenna structure is not in contact with the conductive material.

2. The system of claim 1, wherein a largest dimension of the antenna structure of the RFID device is one-eighth of the wavelength or less.

3. The system of claim 1, wherein the RFID device is at a non-zero angle to the conductive material.

4. The system of claim 3, wherein the RFID device is substantially perpendicular to the conductive material.

5. The system of claim 1, wherein a parallel overlap between the RFID device and the conductive material is 0.5 or less;

and

wherein the parallel overlap is a fraction of area of the antenna structure and a slot of the RFID device that is projected onto the electrically-conductive material, when projection is in a direction perpendicular to the electrically-conductive material.

6. The system of claim 1, wherein the conductive material partially overlaps the RFID device.

7. The system of claim 1, wherein object is attached to the RFID device.

8. The system of claim 7, wherein the RFID device includes a protrusion that maintains the antenna structure at a non-zero angle relative to the conductive material.

9. The system of claim 1, wherein the RFID device is in close proximity to at least one additional RFID device that is also included in the system.

10. The system of claim 9, wherein the close proximity of the RFID devices enhances performance of the RFID devices.

11. The system of claim 1, wherein the RFID device includes:

the antenna structure having antenna-structure electrically conductive material on both sides of an aperture; and

a wireless communication device having a pair of contacts electrically coupled to respective parts of the antenna-structure conductive material; and

wherein the parts of conductive material are electrically coupled together at an end of the aperture distal from the wireless communication device.

12. The system of claim 11, wherein the parts of the conductive material include arms of conductive material.

13. The system of claim 11, wherein the aperture has a substantially rectangular shape.

14. The system of claim 11, wherein the aperture has a pair of borders substantially parallel to one another.

15. The system of claim 11, wherein one end of the aperture is short-circuited between the parts, and the other end of the aperture is not short-circuited between the parts.

16. The system of claim 11,

wherein the wireless communication device is an RFID chip that is part of an RFID interposer;

and

wherein the RFID interposer includes a pair of conductive leads electrically coupled to the parts of the electrically conductive material.

17. The system of claim 11, wherein the wireless communication device and the antenna structure form an antenna with at least two modes of operation.

18. The system of claim 1, wherein the RFID device has an overall size of 2.5 cm ×

2.5 cm or less.

19. An RFID system comprising:

an RFID device; and

an electrically-conductive material that cooperates with the RFID device to enhance performance of the RFID device;

wherein the conductive material is part of an object that the RFID device is attached to;

wherein the RFID device includes a protrusion that maintains an antenna structure at a non-zero angle relative to the conductive material; and

wherein the protrusion has a triangular shape.

20. A method of enhancing performance of an RFID device, the method comprising:

providing the RFID device embodied in a label or tag; and

placing at least part of an antenna structure of the RFID device less than a quarter of a wavelength of energy preferentially received by the RFID device away from an electrically-conductive material that is at least part of an object that is not a part of the label or tag, so as to enhance performance of the RFID device;

wherein the placing includes placing the RFID device such that the antenna structure is not in contact with the conductive material.

21. The method of claim 20, wherein the placing includes placing at least part of the RFID device within a distance to the electrically-conductive conductive material of one-eighth of a wavelength of energy preferentially received by the RFID device.

22. The method of claim 21, wherein the providing includes providing an RFID device that has the antenna structure with no dimension greater than one-eighth of the wavelength.

23. The method of claim 20, wherein the placing include placing the RFID device at a non-zero angle relative to the conductive material.

24. The method of claim 20, wherein the placing includes placing the RFID device substantially perpendicular to the conductive material.

25. The method of claim 20, wherein the placing includes attaching the RFID device to an object that includes the conductive material.

26. The method of claim 20, wherein the enhancing performance includes enhancing read range of the RFID device.

27. The method of claim 20, wherein the providing includes providing an RFID device that includes:

the antenna structure having electrically conductive material on both sides of an aperture; and

a wireless communication device having a pair of contacts electrically coupled to respective parts of the conductive material; and

wherein the parts of conductive material are electrically coupled together at an end of the aperture distal from the wireless communication device.

28. The method of claim 20, wherein the RFID device has an overall size of 2.5 cm ×

2.5 cm or less.