Wireless IC device

• US 8,390,459 B2
• Filed: 07/28/2009
• Issued: 03/05/2013
• Est. Priority Date: 04/06/2007
• Status: Expired due to Fees

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Kato, Noboru
• Primary Examiner(s): MULLEN, THOMAS J
• Application Number:
  US12/510,344
• Publication Number:
  US 20090278687A1
• Time in Patent Office: 1,316 Days
• Field of Search: 340/572.1, 340/572.7, 340/10.1, 235/492, 343/741, 343/742, 343/878
• 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: 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 a first input/output terminal and a second input/output terminal and being arranged to process transmission and reception signals;

a loop electrode including a first end connected to the first input/output terminal and a second end connected to the second input/output terminal; and

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

wherein

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

the loop electrode includes neighboring linear electrodes having different line lengths.

2. The wireless IC device according to claim 1, wherein the neighboring linear electrodes of the loop electrode are electrically connected to the radiation plate at positions different from the first and second ends of the loop electrode.

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

4. The wireless IC device according to claim 1, wherein the neighboring linear electrodes are electrically connected to the radiation plate at different positions.

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

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

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

8. The wireless IC device according to claim 1, further comprising:

a feeder circuit board including a connection electrode arranged to be connected to one of the first and second input/output terminals of the wireless IC chip and a planar electrode electrically connected to the connection electrode.

9. The wireless IC device according to claim 8, wherein an insulating film is arranged on the feeder circuit board so as to cover at least the planar electrode.

10. The wireless IC device according to claim 8, wherein one of the first and second ends of the loop electrode is arranged to face the planar electrode and is connected to the planar electrode through an electric field.

11. The wireless IC device according to claim 8, wherein a plurality of the planar electrodes are arranged on different principal surfaces of the feeder circuit board so as to face each other.

12. The wireless IC device according to claim 11, wherein the facing planar electrodes are electrically connected.

13. The wireless IC device according to claim 8, wherein the feeder circuit board is made of a flexible substrate.

14. The wireless IC device according to claim 8, wherein an insulating film is arranged to cover the planar electrode and to face the radiation plate.