Antenna and wireless IC device

• US 9,104,950 B2
• Filed: 07/26/2011
• Issued: 08/11/2015
• Est. Priority Date: 01/30/2009
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Kato, Noboru, Sasaki, Jun, Miura, Teppei, Gouchi, Naoki
• Primary Examiner(s): Karacsony, Robert
• Assistant Examiner(s): PATEL, AMAL A
• Application Number:
  US13/190,670
• Publication Number:
  US 20110279340A1
• Time in Patent Office: 1,477 Days
• Field of Search: 343/793, 343/906, 343/850, 343/870, 343/867
• US Class Current: 1/1
• 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: 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 1/2283 mounted in or on the surface of a semiconductor substrate as a chip-type antenna or integrated with other components into an IC package
• CPC Class Codes: H01Q 1/36 Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewithH01Q1/08, H01Q1/14 take precedence
• 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

An antenna for a wireless IC device having improved energy transfer efficiency with a wireless IC, and a wireless IC device equipped with the antenna are constructed such that the antenna includes a coil pattern and spiral coupling patterns provided at the ends of the coil pattern and disposed so as to face each other. A coupling module including a wireless IC chip and a feeder circuit substrate including a feeder circuit arranged to be coupled to the wireless IC chip is mounted on the coupling pattern so as to define a wireless IC device. The coil pattern is an open type coil pattern. The coupling patterns are arranged close to each other to define a single LC resonator. Thus, energy is concentrated in the coupling patterns, thereby improving the energy transfer efficiency between the antenna and the wireless IC chip.

Claims

1. A wireless IC device comprising:

a substrate including first and second surfaces that are opposed to each other;

first and second antenna patterns respectively arranged on the first and second surfaces of the substrate so as to face each other, and each including first and second ends;

first and second coupling patterns respectively arranged on the first and second surfaces of the substrate so as to face each other;

a wireless IC; and

a feeder circuit including an inductor arranged to be connected to the wireless IC;

wherein

one end of the first coupling pattern is connected to the first end of the first antenna pattern and another end of the first coupling pattern is open-ended;

one end of the second coupling pattern is connected to the first end of the second antenna pattern and another end of the second coupling pattern is open-ended;

the second end of each of the first and second antenna patterns is open-ended;

the first antenna pattern and the first coupling pattern are wound in the same direction on the first surface of the substrate;

the second antenna pattern and the second coupling pattern are wound in the same direction on the second surface of the substrate;

the first and second coupling patterns are located inside of the first and second antenna patterns in plan view, and provide both capacitive coupling and magnetic-field coupling; and

the inductor of the feeder circuit is magnetically coupled to both of the first and second coupling patterns.

2. The wireless IC device according to claim 1, wherein the first and second antenna patterns are defined by coil-shaped patterns arranged so as to face each other.

3. The wireless IC device according to claim 1, wherein the inductor has a spiral shape such that current flows in the same direction as the first and second coupling patterns.

4. The wireless IC device according to claim 1, wherein a resonant frequency of the feeder circuit substantially corresponds to a resonant frequency of a reception/transmission signal.

5. The wireless IC device according to claim 1, wherein a resonant frequency of the coil-shaped antenna pattern is higher than a resonant frequency of the feeder circuit.

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

a feeder circuit substrate on which the feeder circuit is disposed;

wherein

an area of the coupling patterns is greater than an area of the feeder circuit substrate.

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

a feeder circuit substrate on which the feeder circuit is disposed;

wherein

the feeder circuit substrate is made of a material including a magnetic substance.

8. The wireless IC device according to claim 7, wherein the feeder circuit substrate includes a plurality of layers and a magnetic permeability of a layer of the plurality of layers at a side of a surface that is mounted on the first and second coupling patterns is smaller than at least one other layer of the plurality of layers.