RFID system including a reader/writer and RFID tag

• US 9,727,765 B2
• Filed: 04/27/2012
• Issued: 08/08/2017
• Est. Priority Date: 03/24/2010
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Ikemoto, Nobuo
• Primary Examiner(s): NGUYEN, LAURA N
• Application Number:
  US13/457,525
• Publication Number:
  US 20120206239A1
• Time in Patent Office: 1,929 Days
• Field of Search: 343866, 343741, 343728, 343788, 343856, 343867, 340 101, 455 411- 413, 333 24 R, 333185, 235493
• CPC Class Codes: G06K 7/10346 the antenna being of the far field type, e.g. HF types or dipoles
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01Q 1/2208 associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems methods or arrangements for sensing record carriers, e.g. for reading patterns G06K7/00; record carrier for use with machines and with at least a part designed to carry digital markings G06K19/00
• CPC Class Codes: H01Q 1/40 Radiating elements coated with or embedded in protective material
• CPC Class Codes: H01Q 11/08 Helical antennas
• 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
• CPC Class Codes: H04B 5/26 using coils
• CPC Class Codes: H04B 5/77 for interrogation

Abstract

An RFID system includes an antenna of a reader/writer and an antenna of an RFID tag. Transmission and reception of a high-frequency signal of a UHF band is performed between the antenna of the reader/writer and the antenna of the RFID tag that are arranged so as to be adjacent to each other. A loop antenna including a loop conductor is used as the antenna of the reader/writer, and coil antennas including a plurality of laminated coil conductors are used as the antenna of an RFID tag. In addition, the conductor width of the loop conductor in the loop antenna is greater than the conductor widths of the coil conductors in the coil antennas.

Claims

1. An RFID system comprising:

a reader/writer including an antenna; and

an RFID tag including an antenna attached to an article;

wherein

transmission and reception of a high-frequency signal is performed between the antenna of the reader/writer and the antenna of the RFID tag;

the antenna of the reader/writer is defined by a planar-shaped loop antenna including a loop conductor disposed in a loop plane;

the antenna of the RFID tag is defined by a three-dimensional-shaped coil antenna including a plurality of coil conductors having coil surfaces;

a conductor width of the loop conductor in the planar-shaped loop antenna is greater than a conductor width of each of the plurality of coil conductors in the three-dimensional-shaped coil antenna;

an outside dimension of the loop conductor in the planar-shaped loop antenna is greater than an outside dimension of the plurality of coil conductors in the three-dimensional-shaped coil antenna, such that in the three-dimensional-shaped coil antenna, larger magnetic fields are generated in a direction perpendicular or substantially perpendicular to the coil surfaces than in a direction parallel or substantially parallel to the coil surfaces, and in the planar-shaped loop antenna larger magnetic fields are generated in a direction parallel or substantially parallel to the loop plane than in a direction perpendicular or substantially perpendicular to the loop plane; and

the plurality of coil conductors include portions that are stacked and wound so as to have a three-dimensional shape.

2. The RFID system according to claim 1, wherein the three-dimensional-shaped coil antenna is provided in a power feeding substrate including a plurality of laminated dielectric layers.

3. The RFID system according to claim 2, wherein

the power feeding substrate includes a ceramic laminated body;

and

each of the plurality of laminated dielectric layers is a ceramic dielectric layer.

4. The RFID system according to claim 1, wherein

the three-dimensional-shaped coil antenna includes a first coil antenna and a second coil antenna;

and

the first coil antenna and the second coil antenna are magnetically coupled to each other.

5. The RFID system according to claim 1, wherein the outside dimension of the three-dimensional-shaped coil antenna is less than or equal to 1 cm×

1 cm in planar view.

6. The RFID system according to claim 5, wherein an area occupied by the planar-shaped loop antenna is about 0.2 to about 6 times as large as an area occupied by the three-dimensional-shaped coil antenna, in planar view.

7. The RFID system according to claim 1, wherein the high-frequency signal is a signal of a UHF band or an SHF band.

8. The RFID system according to claim 1, wherein

a largest dimension along outermost edges of the planar-shaped loop antenna is greater than a largest dimension along outermost edges of the three-dimensional-shaped coil antenna;

the antenna of the reader/writer and the antenna of the RFID tag are configured to transmit and receive UHF signals;

the plurality of coil conductors of the three-dimensional-shaped coil antenna are disposed on a plurality of dielectric layers that are laminated to one another; and

outside dimensions of the coil antenna are less than or equal to 1 cm×

1 cm.

9. The RFID system according to claim 1, wherein the loop conductor of the planar-shaped loop antenna is defined by a single-layer loop conductor.

10. The RFID system according to claim 1, wherein the loop conductor of the planar-shaped loop antenna consists of approximately one turn.