Circuit structure and method of fabrication for facilitating radio frequency identification (RFID)

• US 9,013,310 B2
• Filed: 07/24/2008
• Issued: 04/21/2015
• Est. Priority Date: 07/24/2008
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Cho, Choongyeun, Kim, Daeik, Kim, Jonghae, Kim, Moon Ju
• Primary Examiner(s): Bugg, George
• Assistant Examiner(s): SMALL, NAOMI J
• Application Number:
  US12/178,894
• Publication Number:
  US 20100019908A1
• Time in Patent Office: 2,462 Days
• Field of Search: 340/572.7, 343/895, 438/387
• 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: 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 1/248 provided with an AC/DC converting device, e.g. rectennas
• CPC Class Codes: H01Q 23/00 Antennas with active circuits or circuit elements integrated within them or attached to them
• 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

Abstract

A radio frequency identification (RFID) device and method of fabrication are presented. The RFID device includes an RFID antenna, a capacitor, and an RFID integrated circuit. The RFID antenna includes an elongate conductive trace disposed within an antenna area of the RFID device, and the capacitor includes an elongate capacitive structure for storing power. The elongate capacitive structure is aligned with the elongate conductive trace and embedded within the antenna area of the RFID device. The RFID integrated circuit is electrically coupled to the RFID antenna and to the capacitor, and the capacitor stores power within the antenna area of the RFID device to facilitate RFID integrated circuit functionality.

Claims

1. A circuit structure for facilitating radio frequency identification (RFID), the circuit structure comprising:

a multi-layer RFID antenna comprising a first layer and a second layer, the first layer and second layer being parallel layers of the multi-layer RFID antenna, wherein the first layer comprises an upper elongate conductive trace and the second layer comprises a lower elongate conductive trace; and

at least one elongate capacitor separate from and disposed between the first layer and the second layer, the at least one elongate capacitor being aligned with the upper and lower elongate conductive traces in the first layer and the second layer of the RFID antenna, wherein the upper and lower elongate conductive traces of the RFID antenna are disposed in a coil configuration comprising more than one revolution and the at least one elongate capacitor is disposed in a corresponding coil configuration comprising more than one revolution aligned with the coil configuration of the upper and lower elongate conductive traces of the RFID antenna, the coil configuration of the at least one elongate capacitor providing a configuration and sizing of the at least one elongate capacitor to facilitate storage of power for powering an RFID integrated circuit of the circuit structure to facilitate RFID functionality.

2. The circuit structure of claim 1, wherein the at least one elongate capacitor is sized and positioned relative to the upper and lower elongate conductive traces to be hidden electromagnetically by the upper and lower elongate conductive traces from a radio frequency wave to be detected by the RFID antenna when the circuit structure is operationally employed.

3. The circuit structure of claim 2, wherein the at least one elongate capacitor is aligned with and disposed between the upper and lower elongate conductive traces of the RFID antenna.

4. The circuit structure of claim 1, wherein the upper elongate conductive trace and the lower elongate conductive trace are disposed parallel and aligned in spaced opposing relation within the multi-layer RFID antenna.

5. The circuit structure of claim 4, wherein the RFID antenna further comprises at least one side conductive structure electrically connecting the upper elongate conductive trace and the lower elongate conductive trace thereof, wherein the at least one elongate capacitor is disposed spaced apart from, and within a space defined between, the upper elongate conductive trace, the lower elongate conductive trace, and the at least one side conductive structure of the RFID antenna.

6. The circuit structure of claim 1, further comprising a plurality of side conductive structures disposed on a common side of the RFID antenna, the plurality of side conductive structures electrically connecting the upper elongate conducive trace and the lower elongate conductive trace.

7. The circuit structure of claim 6, wherein the plurality of side conductive structures comprises multiple side conductive structures disposed on a first side and multiple side conductive structures disposed on a second side of the RFID antenna, wherein the upper elongate conductive trace, lower elongate conductive trace, and the plurality of side conductive structures electrically connect together and electromagnetically hide the at least one elongate capacitor from a radio frequency wave to be detected by the RFID antenna when the circuit structure is operationally employed.

8. The circuit structure of claim 1, wherein the at least one elongate capacitor comprises multiple, stacked elongate capacitive structures defining multiple elongate capacitors, the multiple, stacked elongate capacitive structures being aligned with the upper and lower elongate conductive traces of the RFID antenna.

9. A radio frequency identification (RFID) device comprising:

a multi-layer RFID antenna comprising a first layer and a second layer, the first layer and second layer being parallel layers of the multi-layer RFID antenna, wherein the first layer comprises an upper elongate conductive trace and the second layer comprises a lower elongate conductive trace, the upper and lower elongate conductive traces being disposed within an antenna area of the RFID device;

at least one elongate capacitor for storing power, the at least one elongate capacitor being embedded within the antenna area of the RFID device and disposed between the first layer and the second layer; and

an RFID integrated circuit electrically coupled to the RFID antenna and to the at least one elongate capacitor, wherein the upper and lower elongate conductive traces of the RFID antenna are disposed in a coil configuration comprising more than one revolution and the at least one elongate capacitor is disposed in a corresponding coil configuration comprising more than one revolution aligned with the coil configuration of the upper and lower elongate conductive traces of the RFID antenna, the coil configuration of the at least one elongate capacitor providing a configuration and sizing of the at least one elongate capacitor to facilitate storage of power for powering the RFID integrated circuit to facilitate RFID integrated circuit functionality.

10. The RFID device of claim 9, wherein the at least one elongate capacitor is aligned with the upper and lower elongate conductive traces of the RFID antenna, and wherein the at least one elongate capacitor is sized and positioned relative to the upper and lower elongate conductive traces to be hidden electromagnetically by the upper and lower elongate conductive traces from a radio frequency wave to be detected by the RFID antenna when the RFID device is operational.

11. The RFID device of claim 9, wherein the at least one elongate capacitor is aligned with and disposed between the upper and lower elongate conductive traces of the RFID antenna.

12. The RFID device of claim 9, wherein the upper elongate conductive trace and the lower elongate conductive trace are disposed parallel and aligned in spaced, opposing relation within the multi-layer RFID antenna.

13. The RFID device of claim 12, wherein the RFID antenna further comprises at least one side conductive structure electrically connecting the upper elongate conductive trace and the lower elongate conductive trace thereof, and wherein the at least one elongate capacitor is disposed spaced apart from, and within a space defined between, the upper elongate conductive trace, the lower elongate conductive trace, and the at least one side conductive structure of the RFID antenna.

14. The RFID device of claim 13, further comprising a plurality of side conductive structures comprising multiple side conductive structures disposed on a first side and multiple side conductive structures disposed on a second side of the RFID antenna, the plurality of side conductive structures electrically connecting the upper elongate conductive trace and the lower elongate conductive trace, and wherein the upper elongate conductive trace, the lower elongate conductive trace, and the plurality of side conductive structures electrically connect together and electromagnetically hide the at least one elongate capacitor from a radio frequency wave to be detected by the RFID antenna when the RFID device is operationally employed.

15. The RFID device of claim 9, wherein the at least one elongate capacitor comprises multiple, stacked elongate capacitive structures defining multiple elongate capacitors, the multiple, stacked elongate capacitive structures being aligned with the upper and lower elongate conductive traces of the RFID antenna within the antenna area of the RFID device.

16. A method of fabricating a circuit structure for facilitating radio frequency identification (RFID), the method comprising:

forming a multi-layer RFID antenna comprising a first layer and a second layer, the first layer and second layer being parallel layers of the multi-layer RFID antenna, wherein the first layer comprises an upper elongate conductive trace and the second layer comprises a lower elongate conductive trace;

providing at least one elongate capacitor disposed between the first layer and the second layer of the multi-layer RFID antenna; and

wherein at least one of forming the RFID antenna or providing the at least one elongate capacitor comprises aligning the at least one elongate capacitor and the upper and lower elongate conductive traces, wherein the upper and lower elongate conductive traces of the RFID antenna are disposed in a coil configuration comprising more than one revolution and the at least one elongate capacitor is disposed in a corresponding coil configuration comprising more than one revolution aligned with the coil configuration of the upper and lower elongate conductive traces of the RFID antenna, the coil configuration of the at least one elongate capacitor providing a configuration and sizing of the at least one elongate capacitor to facilitate storage of power for powering an RFID integrated circuit of the circuit structure to facilitate the RFID.

17. The method of claim 16, wherein the upper elongate conductive trace and the lower elongate conductive trace are disposed parallel and aligned in spaced, opposing relation within the multi-layer RFID antenna.

18. The method of claim 16, wherein providing the at least one elongate capacitor disposed between the first layer and the second layer of the multi-layer RFID antenna comprises providing the at least one elongate capacitor with a size relative to the upper and lower elongate conductive traces to be hidden electromagnetically by the upper and lower elongate conductive traces from a radio frequency wave to be detected by the RFID antenna when the circuit structure is operationally employed.