RFID tag for conductive surface

• US 20070273532A1
• Filed: 05/10/2007
• Published: 11/29/2007
• Est. Priority Date: 05/17/2006
• Status: Abandoned Application

• Current Assignee: Tagsys SAS (Mojix Inc)
• Original Assignee: Tagsys SAS (Mojix Inc)
• Inventors: Martin, Philippe
• Application Number:
  US11/801,681
• Publication Number:
  US 20070273532A1
• Time in Patent Office: Days
• US Class Current: 340/572.700
• CPC Class Codes: G06K 19/04 characterised by the shape
• 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

Abstract

An RFID tag is disclosed for application to a conductive surface. The RFID tag includes an insulating substrate and a first conductive plate provided on the insulating substrate such that the first plate and the conductive surface form a first capacitor, an antenna provided on the substrate and connected to the first capacitor to form a resonant circuit, at least when the tag is applied to the conductive surface, and an integrated circuit connected to the resonant circuit. Preferably, the RFID tag includes a second conductive plate on the substrate, the second plate and conductive surface forming a second capacitor. The two capacitors may be connected in series. A method of applying an RFID tag to a conductive surface is also disclosed.

Claims

1. An RFID tag suitable for application to a conductive surface, said RFID tag including:

an insulating substrate;

a first conductive plate provided on said insulating substrate such that said first plate and said conductive surface form a first capacitor;

an antenna provided on said substrate and connected to said first capacitor to form a resonant circuit at least when said tag is applied to said conductive surface; and

an integrated circuit connected to said resonant circuit.

2. An RFID tag according to claim 1 including a second conductive plate included on said substrate such that said second plate and said conductive surface form a second capacitor, said second capacitor being connected to said resonant circuit.

3. An RFID tag according to claim 2 wherein said first and second capacitors are connected in series via said conductive surface.

4. An RFID tag according to claim 1 wherein said first conductive plate is substantially penannular.

5. An RFID tag according to claim 2 wherein said second conductive plate is substantially penannular.

6. An RFID tag according to claim 1 wherein said antenna comprises a spiral conductor.

7. An RFID tag according to claim 1 wherein the area of said tag comprises a substantial portion of the area of said conductive surface.

8. A method of applying an RFID tag to a conductive surface, said method including:

providing an insulating substrate on said conductive surface;

providing a first conductive plate on said insulating surface such that said first plate and said conductive surface form a first capacitor;

providing an antenna on said substrate and connecting said antenna to said first capacitor to form a resonant circuit at least when said tag is applied to said conductive surface; and

connecting an integrated circuit to said resonant circuit.

9. A method according to claim 8 including providing a second conductive plate on said substrate such that said second plate and said conductive surface form a second capacitor, said second capacitor being connected to said resonant circuit.

10. A method according to claim 9 wherein said first and second capacitors are connected in series via said conductive surface.

11. A method according to claim 8 wherein said first conductive plate is substantially penannular.

12. A method according to claim 9 wherein said second conductive plate is substantially penannular.

13. A method according to claim 8 wherein said antenna comprises a spiral conductor.

14. A method according to claim 8 wherein the area of said tag comprises a substantial portion of the area of said conductive surface.