Method of Using Shielded RFID Straps with RFID Tag Designs

• US 20190325285A1
• Filed: 04/19/2019
• Published: 10/24/2019
• Est. Priority Date: 04/20/2018
• Status: Active Grant

• Current Assignee: Avery Dennison Retail Information Services LLC (Avery Dennison Corporation)
• Original Assignee: Avery Dennison Retail Information Services LLC (Avery Dennison Corporation)
• Inventors: FORSTER, Ian J., Howard, Norman A., MCGINNISS, Edward J.
• Granted Patent: US 11,120,323 B2
• Time in Patent Office: Days
• CPC Class Codes: G06K 19/07718 the record carrier being manufactured in a continuous process, e.g. using endless rolls
• CPC Class Codes: G06K 19/07752 using an interposer
• CPC Class Codes: G06K 19/07756 the connection being non-galvanic, e.g. capacitive
• CPC Class Codes: G06K 19/07788 the antenna being of the capacitive type

Abstract

A method of using shielded straps with RFID tag designs is disclosed. Specifically, the RFID device, in one embodiment, comprises a bridge conductor which couples the antenna and pair of strap pads together. Thus, the coupling between the bridge conductor and the strap conductor, the coupling between the bridge conductor and the antenna conductor, and the coupling between the antenna conductor and the strap conductor increases the total capacitance of the RFID strap device. Further, the presence of the bridge conductor also reduces the area occupied for a given inductance, and provides a higher effective capacitance when the bridge strap is connected to the antenna.

Claims

1. A radio-frequency identification (RFID) device comprising:

a first conductor comprised of at least one pair of strap pads and an RFID chip connected to the at least one pair of strap pads;

a second conductor; and

a dielectric positioned between the first conductor and the second conductor, wherein the first strap conductor couples to an antenna conductor.

2. The RFID device of claim 1, wherein the at least one pair of strap pads is coupled to the antenna conductor via a conductive adhesive.

3. The RFID device of claim 1, wherein the at least one pair of strap pads is coupled to the antenna conductor via capacitance.

4. The RFID device of claim 1, wherein the antenna conductor is attached to a base substrate.

5. The RFID device of claim 1, wherein the second conductor is a bridge and the second conductor, the first strap conductor, and the antenna conductor overlap each other to provide a mutual area with separating dielectrics and a plurality of capacitors having a value.

6. The RFID device of claim 5, wherein the value of the plurality of capacitors is determined by (i) the mutual area, (ii) a dielectric constant of a material between the antenna conductor, the first strap conductor and the second conductor, and (iii) an amount of distance separating the antenna conductor, the first strap conductor and the second conductor.

7. The RFID device of claim 1, wherein an area of the second conductor is larger than an area of the pair of strap pads.

8. The RFID device of claim 1, wherein an area of the second conductor is smaller than an area of the at least one pair of strap pads.

9. The RFID device of claim 1, wherein the second conductor is modified via a cutting process.

10. The RFID device of claim 1 wherein a shape and an area of the second conductor is modified via a cutting process.

11. The RFID device of claim 9, wherein the cutting process is a laser cut line.

12. A radio-frequency identification (RFID) strap device comprising:

a first strap conductor comprised of a pair of strap pads and an RFID chip connected between the pair of strap pads;

a second bridge conductor; and

a dielectric positioned between the first strap conductor and the second bridge conductor, wherein the first strap conductor couples to an antenna conductor, and further wherein the second bridge conductor, the first strap conductor, and the antenna conductor overlap each other to provide a mutual area with separating dielectrics and a plurality of capacitors having a value.

13. The RFID strap device of claim 12, wherein the value of the plurality of capacitors is determined by the (i) mutual area, (ii) a dielectric constant of a material between the antenna conductor, the first strap conductor, and the second bridge conductor, and (iii) an amount of distance separating the antenna conductor, the first strap conductor and the second bridge conductor.

14. The RFID strap device of claim 12, wherein an area of the bridge conductor is larger than an area of the pair of strap pads.

15. The RFID strap device of claim 12, wherein an area of the bridge conductor is smaller than an area of the pair of strap pads.

16. The RFID strap device of claim 12, wherein the second bridge conductor is modified via a cutting process.

17. A method of making shielded straps having an increased capacitance across a RFID device comprising:

providing a bridge conductor, a pair of strap pads, and an antenna conductor;

attaching the antenna conductor to the pair of strap pads; and

attaching the bridge conductor to the pair of strap pads.

18. The method of claim 17, further comprising modifying one or more of a shape and an area of the bridge conductor via a cutting process.

19. The method of claim 17, wherein the cutting process is performed before attaching the antenna conductor to the pair of strap pads.

20. The method of claim 17, wherein the cutting process is performed after attaching the antenna conductor to the pair of strap pads.