ANTENNA AND ANTENNA MODULE

• US 20120092222A1
• Filed: 12/22/2011
• Published: 04/19/2012
• Est. Priority Date: 07/03/2009
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: KATO, Noboru, TANIGUCHI, Katsumi, IKEMOTO, Nobuo, MURAYAMA, Hiromi
• Granted Patent: US 8,847,831 B2
• Time in Patent Office: Days
• US Class Current: 343/742
• CPC Class Codes: G08B 13/00 Burglar, theft or intruder alarms
• CPC Class Codes: H01Q 21/0025 Modular arrays
• 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

Abstract

An antenna includes a flexible sheet that includes a first main surface including a first coil electrode located thereon and a second main surface including a second coil electrode located thereon. The first and second coil electrodes are wound in opposite directions when viewed from different directions. A first end of the first coil electrode faces a first end of the second coil electrode through the flexible sheet. Similarly, a second end of the first coil electrode faces a second end of the second coil electrode through the flexible sheet. The first and second coil electrodes define an inductor, the first ends of the first and second coil electrodes define a capacitor, and the second ends of the first and second coil electrodes define a capacitor whereby a resonant antenna is provided.

Claims

1. An antenna comprising:

an insulation base member including first and second main surfaces which face each other;

a first coil electrode arranged on the first main surface in a winding manner and including end portions; and

a second coil electrode arranged on the second main surface, wound in a direction opposite to a winding direction of the first coil electrode when viewed in a direction from the second main surface to the first main surface, and including end portions;

wherein

an end portion of the first coil electrode and an end portion of the second coil electrode at least partially face each other.

2. The antenna according to claim 1, wherein at least one of the end portions of the first coil electrode and at least one of the end portions of the second coil electrode include flat electrodes having electrode widths larger than that of the first coil electrode and that of the second coil electrode, respectively.

3. The antenna according to claim 2, wherein both of the end portions of the first coil electrode and both of the end portions of the second coil electrode include flat electrodes having electrode widths larger than that of the first coil electrode and that of the second coil electrode, respectively, and one of the end portions of the first coil electrode faces one of the end portions of the second coil electrode and the other of the end portions of the first coil electrode faces the other of the end portions of the second coil electrode.

4. The antenna according to claim 1, wherein one of the end portions of the first coil electrode and one of the end portions of the second coil electrode have winding shapes, and the end portion having the winding shape of the first coil electrode faces the end portion having the winding shape of the second coil electrode.

5. The antenna according to claim 4, wherein the end portions having the winding shapes are positioned substantially in centers of regions defined in the first and second coil electrodes.

6. The antenna according to claim 1, further comprising at least one of a flat electrode located on the first main surface so as to be adjacent to the first coil electrode and a flat electrode located on the second main surface so as to be adjacent to the second coil electrode.

7. An antenna module comprising:

the antenna according to claim 1; and

a wireless communication IC which is disposed on the insulation base member so as to be electrically connected to the first coil electrode or the second coil electrode.

8. The antenna module according to claim 7, wherein the wireless communication IC is connected to a center electrode included in a group of electrodes which are included in the first coil electrode or the second coil electrode and which are arranged in parallel or substantially in parallel in a winding manner.

9. An antenna module comprising:

the antenna according to claim 1; and

an electromagnetic coupling module including a wireless communication IC and a power-supply circuit board arranged to supply power to the wireless communication IC;

wherein

the electromagnetic coupling module includes an inductor and is disposed on the insulation base member so that the inductor is electromagnetically coupled with the first coil electrode or the second coil electrode.

10. The antenna module according to claim 9, wherein the electromagnetic coupling module is disposed on the first coil electrode or the second coil electrode.

11. The antenna module according to claim 10, wherein the electromagnetic coupling module is disposed on a center electrode included in a group of electrodes which are included in the first coil electrode or the second coil electrode and which are arranged in parallel or substantially in parallel in a winding manner.

12. The antenna module according to claim 10, wherein the electromagnetic coupling module is disposed such that the electromagnetic coupling module is electromagnetically coupled with only one of the electrodes included in the first coil electrode or the second coil electrode.

13. An antenna module comprising:

the antenna according to claim 4; and

an electromagnetic coupling module including a wireless communication IC and a power-supply circuit board arranged to supply power to the wireless communication IC;

wherein

the electromagnetic coupling module includes an inductor and is disposed in a position which substantially corresponds to the end portion having the winding shape when the first main surface of the insulation base member is viewed in a planar manner.

14. An antenna module comprising:

the antenna according to claim 1; and

a base antenna arranged to generate a magnetic field in accordance with communication data supplied to a wireless communication IC;

wherein

the antenna is disposed separately from the base antenna with a predetermined gap interposed therebetween.