Wireless IC device and coupling method for power feeding circuit and radiation plate

• US 8,810,456 B2
• Filed: 12/14/2011
• Issued: 08/19/2014
• Est. Priority Date: 06/19/2009
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Kato, Noboru
• Primary Examiner(s): Nguyen, Hoang V
• Application Number:
  US13/325,273
• Publication Number:
  US 20120086526A1
• Time in Patent Office: 979 Days
• Field of Search: 343/850, 343/700.MS, 343/895
• US Class Current: 343/700.MS
• 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 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: H01Q 9/285 Planar dipole H01Q9/065 takes precedence; patch antenna H01Q9/0407

Abstract

A wireless IC device includes a wireless IC chip, a power feeding circuit substrate including a power feeding circuit including inductance elements, and radiation plates including plate-shaped coupling units. The inductance elements have spiral shapes and are wound in directions opposite to each other. The plate-shaped coupling units in the radiation plates are disposed in a vicinity of the inductance elements so as to be perpendicular or substantially perpendicular to the winding axes of the inductance elements, and eddy currents occur in the plate-shaped coupling units so as to couple the power feeding circuit and the radiation plates with each other. The plate-shaped coupling units may also have spiral shapes.

Claims

1. A wireless IC device, comprising

a wireless IC;

a power feeding circuit coupled with the wireless IC and including a resonant circuit and/or a matching circuit including at least two inductance elements; and

a radiation plate arranged to radiate a transmission signal supplied from the power feeding circuit and/or supply a received signal to the power feeding circuit;

wherein

the at least two inductance elements are spiral shaped and wound in directions opposite to each other and winding axes of each of the at least two individual inductance elements are disposed at different positions; and

the radiation plate includes two spiral-shaped coupling units, the spiral-shaped coupling units are disposed in a vicinity of the at least two inductance elements so that spiral surfaces thereof are nearly perpendicular to the winding axes of the at least two inductance elements, respectively, and the spiral-shaped coupling units are wound in directions opposite to the winding directions of the at least two inductance elements adjacent to the spiral-shaped coupling units, respectively.

2. The wireless IC device according to claim 1, wherein the radiation plate includes one conductive wire.

3. The wireless IC device according to claim 1, wherein a length of the radiation plate is an integral multiple of λ

/2.

4. A coupling method for a power feeding circuit including a resonant circuit and/or a matching circuit including at least two inductance elements and a radiation plate arranged to radiate a transmission signal supplied from the power feeding circuit and/or supply a received signal to the power feeding circuit;

wherein

the at least two inductance elements are spiral shaped and wound in directions opposite to each other and winding axes of the at least two inductance elements are disposed at different positions;

the radiation plate includes two spiral-shaped coupling units; and

the two spiral-shaped coupling units are disposed in a vicinity of the at least two inductance elements so that spiral surfaces thereof are nearly perpendicular to the winding axes of the at least two inductance elements, respectively, the spiral-shaped coupling units are wound in directions opposite to the winding directions of the inductance elements adjacent to the spiral-shaped coupling units, respectively, and eddy currents are caused to occur in the two spiral-shaped coupling units so as to couple the power feeding circuit and the radiation plate with each other.