Antenna and radio IC device

• US 8,081,125 B2
• Filed: 01/08/2009
• Issued: 12/20/2011
• Est. Priority Date: 07/11/2006
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Dokai, Yuya, Kato, Noboru
• Primary Examiner(s): LE, HOANGANH T
• Application Number:
  US12/350,307
• Publication Number:
  US 20090109102A1
• Time in Patent Office: 1,076 Days
• Field of Search: 343/702, 343/700.MS
• US Class Current: 343/702
• 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 19/07779 the inductive antenna being a coil
• CPC Class Codes: G06K 19/07783 the coil being planar
• CPC Class Codes: G06K 19/07784 the inductive antenna consisting of a plurality of coils stacked on top of one another
• CPC Class Codes: G06K 19/07786 the antenna being of the HF type, such as a dipole
• CPC Class Codes: G06K 7/10178 including auxiliary means for focusing, repeating or boosting the electromagnetic interrogation field comparable booster antennas integrated on the record carrier itself G06K19/07794
• 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 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00

Abstract

An antenna includes a feeder terminal and a resonance circuit. The resonance circuit is defined by a capacitance element and an inductance element and includes first and second radiation plates. The capacitance element is electromagnetically coupled to the first radiation plate, and the inductance element is electromagnetically coupled to the second radiation plate. A radio IC device includes an electromagnetic coupling module including a feeder circuit substrate on which a radio IC chip is mounted, and radiation plates. The feeder circuit substrate includes an inductance element and a capacitance element. One of the radiation plates faces and is magnetically coupled to the inductance element. The other radiation plate faces and is electrically coupled to the capacitance element. The radio IC chip is operated by signals received by the radiation plates, and a response signal from the radio IC chip is radiated from the radiation plates.

Claims

1. An antenna comprising:

a feeder terminal;

a resonance circuit including at least a capacitance element and an inductance element;

a first radiation element electromagnetically coupled to the capacitance element; and

a second radiation element electromagnetically coupled to the inductance element;

wherein

one of the first radiation element or the second radiation element is substantially circular and includes an end directly connected to the other one of the first radiation element or the second radiation element.

2. The antenna according to claim 1, further comprising an antenna substrate including the resonance circuit.

3. The antenna according to claim 2, wherein the feeder terminal is arranged on a first principal surface of the antenna substrate and the first and second radiation elements are arranged on a second principal surface of the antenna substrate.

4. The antenna according to claim 2, wherein the capacitance element and the inductance element are included in the antenna substrate and arranged substantially parallel to each other.

5. The antenna according to claim 1, wherein the resonance circuit comprises a plurality of resonance circuits.

6. A radio IC device comprising:

a radio IC chip arranged to process transmission and reception signals;

a feeder circuit substrate including an inductance element electrode and a capacitance element electrode defining a resonance circuit, the electrodes being arranged at different locations in a plan perspective view;

a first radiation plate arranged to face the inductance element electrode; and

a second radiation plate arranged to face the capacitance element electrode;

wherein

the radio IC chip is mounted on the feeder circuit substrate, to define an electromagnetic coupling module; and

the radio IC chip is operated by signals received by the first and second radiation plates and a response signal from the radio IC chip is radiated from the first and second radiation plates to outside.

7. The radio IC device according to claim 6, wherein an area of the second radiation plate is greater than that of the first radiation plate.

8. The radio IC device according to claim 6, wherein the first radiation plate has a line length of an integral multiple of a half wavelength of a resonance frequency of the radio IC device.

9. The radio IC device according to claim 6, wherein the first and second radiation plates are arranged such that longitudinal sides of the radiation plates are in substantially the same orientation.

10. The radio IC device according to claim 6, wherein at least one of the first and second radiation plates branches at an approximate middle portion in a longitudinal direction thereof.

11. The radio IC device according to claim 6, wherein at least one of the first and second radiation plates branches at a root portion with a predetermined angle.

12. The radio IC device according to claim 6, wherein the feeder circuit substrate comprises a multilayer substrate.

13. The radio IC device according to claim 6, wherein the feeder circuit substrate comprises a flexible substrate.