RFID tag with enhanced readability

• US 8,072,334 B2
• Filed: 10/09/2007
• Issued: 12/06/2011
• 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: Forster, Ian J., Puleston, David J.
• Primary Examiner(s): Lee, Benjamin C
• Assistant Examiner(s): WILSON, BRIAN P
• Application Number:
  US11/869,210
• Publication Number:
  US 20080024308A1
• Time in Patent Office: 1,519 Days
• Field of Search: None
• US Class Current: 340/572.7
• 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) device includes a conductive antenna structure having an elongated slot therein. Parts of the antenna structure on both sides of one end of the elongated slot are coupled to a wireless communication device, such as an RFID chip or interposer. On the opposite end of the elongated slot, parts of the antenna structure at both sides of the elongated slot are electrically coupled together, for instance by being coupled together by other conductive parts of the antenna structure. All of the parts of the antenna structure may be parts of a continuous unitary layer of conductive material. The antenna structure with the elongated slot therein may facilitate increased readability of the RFID device, particularly in directions out from the edges of the RFID device.

Claims

1. A method of communicating with one or more of plural radio frequency identification (RFID) devices, the method comprising:

providing a plurality of RFID devices with each of the RFID devices having an antenna of conductive material with each antenna having a dimension;

moving the RFID devices within a close proximity of one another to be within about twice the dimension of the antenna to enhance the performance of the RFID devices;

wherein the enhancing performance includes increasing at least one of read distance for the devices or signal strength for the RFID devices; and

communicating with wireless communication devices of the one or more of the RFID devices.

2. The method of claim 1, wherein each of the RFID devices has an overall size of 8 cm×

8 cm or less.

3. The method of claim 1, wherein the enhancing readability includes placing the RFID devices in a container.

4. The method of claim 1, wherein the enhancing readability includes placing the RFID devices in a carton.

5. The method of claim 1, wherein the enhancing readability includes placing the RFID devices in a display.

6. The method of claim 1, wherein the enhancing readability includes placing the RFID devices on a shelf.

7. The method of claim 1, wherein the enhancing includes placing at least some of the RFID devices in the vicinity of electrically conductive material.

8. The method of claim 1, wherein the enhancing includes placing at least some of the RFID devices in a substantially planar array.

9. A group of objects to be tracked, the group comprising:

the objects;

wherein each of the objects has a radio frequency identification (RFID) device thereupon and each of the RFID devices having an antenna of conductive material with each antenna having a dimension; and

wherein the RFID devices are in close proximity to one another, with each of the RFID devices being within about twice a longest dimension of the conductive material of the RFID devices of another of the RFID devices, thereby increasing at least one of read distance for the devices or signal strength for the RFID devices.

10. The group of claim 9, in combination with a display device that the objects are on.

11. The combination of claim 10, wherein the display device includes a shelf.

12. The combination of claim 10, wherein the display device includes an electrically-conductive material that is not part of the RFID devices, but cooperates with the RFID devices to enhance performance of the RFID devices.

13. The group of claim 9, in combination with a container that the objects are in.

14. The group of claim 9, in combination with a carton that the objects are in.

15. The group of claim 9, wherein each of the RFID devices includes:

an antenna structure having electrically conductive material on both sides of an elongated slot; and

one of the wireless communication devices, the 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 elongated slot distal from the wireless communication device.

16. A display and tracking system comprising:

a display unit;

a group of items positioned on the display unit, wherein each of the items has an RFID device; and

a reader capable of reading the RFID devices;

wherein the display unit includes one or more antennas coupled to the reader;

wherein the system can read the RFID devices in a variety of orientations; and

wherein the RFID devices are in close proximity to one another, with each of the RFID devices being within about twice a longest dimension of conductive material of the RFID devices of another of the RFID devices, thereby increasing at least one of read distance for the devices or signal strength for the RFID devices.

17. The system of claim 16, wherein the display unit includes a shelf.

18. The system of claim 16, wherein the one or more antennas includes multiple antennas.