Self-tuning Radio-Frequency Identification tags
A radio-frequency identification (RFID) tag, wherein an operational characteristic of the tag is susceptible to influence by a material comprising an object to which it is attached, comprising: a substrate comprising an attachment region and a flap region, the attachment region for coupling the RFID tag to a surface of an object; and, an RFID inlay formed on the substrate, comprising a loop antenna and a dipole antenna, the loop antenna and the dipole antenna each having first and second portions within the attachment and flap regions, respectively, wherein a relative portion of the loop antenna within the attachment region has a positive influence on the operational characteristic when attached to an object and a relative portion of the dipole antenna within the attachment region has a negative influence on the operational characteristic, whereby the net influence on the operational characteristic by the object can be minimized.
1. A radio-frequency identification (RFID) tag for use on an object, wherein an operational characteristic of said RFID tag is susceptible to influence by a material comprising said object, said RFID tag comprising:
a substrate comprising an attachment region and a flap region, said attachment region adapted for coupling said RFID tag to a surface of said object; and
an RFID inlay formed on said substrate, said RFID inlay comprising a loop antenna and a dipole antenna, said loop antenna and said dipole antenna each having first and second portions within said flap and attachment regions, respectively, wherein said second portion of said loop antenna within said attachment region has a relative positive influence on said operational characteristic when attached to said object and said second portion of said dipole antenna within said attachment region has a relative negative influence on said operational characteristic, whereby a net influence on said operational characteristic of said material comprising said object to which said RFID tag will be attached can be minimized.
2. The RFID tag recited in claim 1 , wherein said substrate is physically defined by a first edge and a second edge and a central folding location, said attachment region comprising a region of said substrate between said central folding location and said first edge and said flap region comprising a region of said substrate between said central folding location and said second edge.
3. The RFID tag recited in claim 1 , wherein said relative positive influence of said loop antenna within said attachment region on said operational characteristic increases with a surface area of said object to which said attachment region is coupled.
4. The RFID tag recited in claim 1 , wherein said relative negative influence of said dipole antenna within said attachment region on said operational characteristic increases with a surface area of said object to which said attachment region is coupled.
5. The RFID tag recited in claim 1 , wherein said operational characteristic is a power on tag forward required to effectively read said RFID tag at a desired operational frequency.
6. The RFID tag recited in claim 5 , wherein said desired operational frequency is within a 902-928 MHz band.
7. The RFID tag recited in claim 5 , wherein said power on tag forward is relatively consistent for use of said RFID tag on objects comprising substantially different materials.
8. The RFID tag recited in claim 1 , wherein said operational characteristic is a sensitivity of said RFID tag at a desired operational frequency.
9. The RFID tag recited in claim 1 , wherein said first and second portions of said dipole antenna originate at a location within said flap region.
10. The RFID tag recited in claim 9 , wherein said first portion of said dipole antenna is wholly positioned within said flap region of said substrate and wherein said second portion of said dipole antenna extends from said flap region into said attachment region of said substrate.
11. The RFID tag recited in claim 9 , wherein said first and second portions of said dipole antenna within said flap region and said attachment region, respectively, are not symmetrical.
12. The RFID tag recited in claim 1 , wherein said first and second portions of said loop antenna are primary and secondary portions, respectively, and at least a part of said secondary portion is positioned within said attachment region.
13. The RFID tag recited in claim 12 , wherein said secondary portion of said loop antenna comprises an elongated stub.
14. The RFID tag recited in claim 13 , wherein said elongated stub is oriented such that progressively more of said elongated stub overlays said object as a greater area of said attachment region is affixed to said object.
15. The RFID tag recited in claim 1 , wherein said object to which said RFID tag can be attached comprises a container formed from metal, paper, plastic, or glass.
16. The RFID tag recited in claim 15 , wherein said object further comprises a material within said container.
17. The RFID tag recited in claim 16 , wherein said material within said container comprises a liquid.
18. The RFID tag recited in claim 1 , wherein said flap region of said substrate is adapted to extend away from said surface of said object.
19. The RFID tag recited in claim 1 , wherein said substrate comprises first and second opposing surfaces and said RFID inlay is located on only said first surface.
20. The RFID tag recited in claim 1 , further comprising an adhesive means disposed on at least a portion of said substrate in said attachment region, said adhesive means suitable for fixedly attaching said RFID tag to said surface of said object.
21. The RFID tag recited in claim 1 , wherein said RFID tag is passive.