WIRELESS IC DEVICE

• US 20090278687A1
• Filed: 07/28/2009
• Published: 11/12/2009
• Est. Priority Date: 04/06/2007
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Kato, Noboru
• Granted Patent: US 8,390,459 B2
• Time in Patent Office: Days
• US Class Current: 340/572.100
• 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 19/07756 the connection being non-galvanic, e.g. capacitive
• CPC Class Codes: G06K 19/07786 the antenna being of the HF type, such as a dipole
• 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 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 1/40 Radiating elements coated with or embedded in protective material
• CPC Class Codes: H01Q 9/24 Shunt feed arrangements to single active elements, e.g. for delta matching
• CPC Class Codes: H01Q 9/26 with folded element or elements, the folded parts being spaced apart a small fraction of operating wavelength resonant loop antennas H01Q7/00

Abstract

A wireless IC device includes an electromagnetic coupling module, which includes a feeder circuit board having a wireless IC chip arranged to process transmission and reception signals mounted thereon, and a radiation plate. Linear loop electrodes provided in the radiation plate are electromagnetically coupled to planar electrodes located on a surface of the feeder circuit board. A signal received by the radiation plate drives the wireless IC chip. A response signal from the wireless IC chip is transmitted to the outside from the radiation plate. A frequency of the transmission and reception signals is substantially determined by inductance of the loop electrodes, capacitance between the loop electrodes and the planar electrodes, and stray capacitance generated between lines of the loop electrodes.

Claims

1. A wireless IC device comprising:

a wireless IC chip including an input/output terminal and being arranged to process transmission and reception signals;

a feeder circuit board including a connection electrode to be connected to the input/output terminal and a planar electrode electrically connected to the connection electrode provided thereon;

a linear electrode arranged to be electromagnetically coupled to the planar electrode; and

a radiation plate arranged to be electrically connected to the linear electrode;

wherein

the wireless IC chip is mounted on the feeder circuit board to constitute an electromagnetic coupling module; and

a signal received by the radiation plate drives the wireless IC chip and a response signal from the wireless IC chip is transmitted to outside from the radiation plate; and

a frequency of a signal to be transmitted and received by the radiation plate is substantially determined by inductance of the linear electrode and capacitance between the linear electrode and the planar electrode.

2. The wireless IC device according to claim 1, wherein an insulating film is arranged on the feeder circuit board so as to cover at least the planar electrode.

3. The wireless IC device according to claim 1, wherein the linear electrode is constituted by a plurality of neighboring electrodes.

4. The wireless IC device according to claim 1, wherein an end portion of the linear electrode is arranged to face the planar electrode and is coupled to the planar electrode through an electric field.

5. The wireless IC device according to claim 4, wherein the linear electrode includes a plurality of loop electrodes.

6. The wireless IC device according to claim 5, wherein the plurality of loop electrodes are electrically connected to the radiation plate at a position different from that of the end portion.

7. The wireless IC device according to claim 1, wherein the linear electrode and the radiation plate are located on a common substrate.

8. The wireless IC device according to claim 1, wherein a plurality of the linear electrodes are electrically connected to the radiation plate at different positions.

9. The wireless IC device according to claim 1, wherein a plurality of the planar electrodes are arranged on different principal surfaces of the feeder circuit board so as to face each other.

10. The wireless IC device according to claim 9, wherein the facing planar electrodes are electrically connected.

11. The wireless IC device according to claim 1, wherein the linear electrode and the radiation plate are symmetrically arranged with respect to the wireless IC chip.

12. The wireless IC device according to claim 1, wherein the feeder circuit board is made of a flexible substrate.

13. The wireless IC device according to claim 1, further comprising a flexible substrate upon which the linear electrode and the radiation plate are disposed.

14. The wireless IC device according to claim 1, wherein an insulating film is arranged to cover the radiation plate.

15. The wireless IC device according to claim 2, wherein an insulating film is arranged to cover the planar electrode and to face the radiation plate.