CIRCUIT STRUCTURE AND METHOD OF FABRICATION FOR FACILITATING RADIO FREQUENCY IDENTIFICATION (RFID)

• US 20100019908A1
• Filed: 07/24/2008
• Published: 01/28/2010
• Est. Priority Date: 07/24/2008
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: KIM, Moon Ju, KIM, Jonghae, KIM, Daeik, CHO, Choongyeun
• Granted Patent: US 9,013,310 B2
• Time in Patent Office: Days
• US Class Current: 340/572.700
• 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:

an RFID antenna comprising an elongate conductive trace; and

a capacitor comprising at least one elongate capacitive structure, the at least one elongate capacitive structure being aligned with the elongate conductive trace of the RFID antenna, wherein the capacitor stores power and thereby facilitates RFID functionality.

2. The circuit structure of claim 1, wherein the at least one elongate capacitive structure is sized and positioned relative to the elongate conductive trace to be hidden electromagnetically by the elongate conductive trace 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 capacitive structure is aligned with and disposed beneath the elongate conductive trace of the RFID antenna.

4. The circuit structure of claim 1, wherein the elongate conductive trace of the RFID antenna is a first elongate conductive trace, and wherein the RFID antenna is a multi-layer structure further comprising a second elongate conductive trace, the first elongate conductive trace and the second elongate conductive trace being disposed parallel and aligned in spaced opposing relation within the multi-layer structure, and wherein the elongate capacitive structure is disposed between the first elongate conductive trace and the second elongate conductive trace of the RFID antenna.

5. The circuit structure of claim 4, wherein the RFID antenna further comprises at least one side conductive structure electrically connecting the first elongate conductive trace and the second elongate conductive trace thereof, wherein the elongate capacitive structure is disposed within a space defined between the first elongate conductive trace, the second elongate conductive trace, and the at least one side conductive structure of the RFID antenna.

6. The circuit structure of claim 5, further comprising a plurality of side conductive structures disposed on at least one side of the RFID antenna, the plurality of side conductive structures electrically connecting the first elongate conducive trace and the second elongate conductive trace.

7. The circuit structure of claim 6, wherein the plurality of side conductive structures comprises side conductive structures disposed on a first side and side conductive structures disposed on a second side of the RFID antenna, wherein the first elongate conductive trace, second elongate conductive trace, and the plurality of side conductive structures electrically connect together and electromagnetically hide the elongate capacitive structure 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 elongate conductive trace of the RFID antenna is disposed in a coil configuration, and the at least one elongate capacitive structure of the capacitor is disposed in a corresponding coil configuration aligned with the coil configuration of the elongate conductive trace of the RFID antenna.

9. The circuit structure of claim 1, wherein the capacitor comprises multiple, stacked elongate capacitive structures, the multiple, stacked elongate capacitive structures being aligned with the elongate conductive trace of the RFID antenna.

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

an RFID antenna comprising an elongate conductive trace disposed within an antenna area of the RFID device;

a capacitor comprising at least one elongate capacitive structure for storing power, the at least one elongate capacitive structure being embedded within the antenna area of the RFID device; and

an RFID integrated circuit electrically coupled to the RFID antenna and to the capacitor, wherein the capacitor stores power within the antenna area of the RFID device to facilitate RFID integrated circuit functionality.

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

12. The RFID device of claim 10, wherein the at least one elongate capacitive structure is aligned with and disposed beneath the elongate conductive trace of the RFID antenna.

13. The RFID device of claim 10, wherein the elongate conductive trace of the RFID antenna is a first elongate conductive trace, and wherein the RFID antenna is a multi-layer structure further comprising a second elongate conductive trace, the first elongate conductive trace and the second elongate conductive trace being disposed parallel and aligned in spaced, opposing relation within the multi-layer structure, and wherein the elongate capacitive structure is disposed between the first elongate conductive trace and the second elongate of the RFID antenna.

14. The RFID device of claim 13, wherein the RFID antenna further comprises at least one side conductive structure electrically connecting the first elongate conductive trace and the second elongate conductive trace thereof, and wherein the elongate capacitive structure is disposed within a space defined between the first elongate conductive trace, the second elongate conductive trace, and the at least one side conductive structure of the RFID antenna.

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

16. The RFID device of claim 10, wherein the elongate conductive trace of the RFID antenna is disposed in a coil configuration within the antenna area, and the at least one elongate capacitive structure of the capacitor is disposed in a corresponding coil configuration within the antenna area aligned with the coil configuration of the elongate conductive trace of the RFID antenna.

17. The RFID device of claim 10, wherein the capacitor comprises multiple, stacked elongate capacitive structures, the multiple, stacked elongate capacitive structures being aligned with the elongate conductive trace of the RFID antenna within the antenna area of the RFID device.

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

forming an RFID antenna comprising an elongate conductive trace;

forming a capacitor comprising at least one elongate capacitive structure; and

wherein at least one of forming the RFID antenna or forming the capacitor comprises aligning the at least one elongate capacitive structure and the elongate conductive trace, and wherein forming the capacitor further comprises sizing the capacitor relative to the elongate conductive trace to be hidden electromagnetically by the elongate conductive trace from a radio frequency wave to be detected by the RFID antenna when the circuit structure is operationally employed.

19. The method of claim 18, wherein the elongate conductive trace of the RFID antenna is a first elongate conductive trace, and wherein forming the RFID antenna comprises forming the RFID antenna as a multi-layer structure comprising a second elongate conductive trace, the first elongate conductive trace and the second elongate conductive trace being disposed parallel and aligned in spaced, opposing relation within the multi-layer structure, and wherein the forming of the RFID antenna and the forming of the capacitor result in the at least one elongate capacitive structure being disposed between the first elongate conductive trace and the second elongate conductive trace of the RFID antenna.

20. The method of claim 18, wherein forming the RFID antenna comprises forming the elongate conductive trace of the RFID antenna in a coil configuration, and wherein forming the capacitor comprises forming the at least one elongate capacitive structure in a corresponding coil configuration aligned with the coil configuration of the elongate conductive trace of the RFID antenna.