Antenna apparatus and communication terminal instrument

• US 9,558,384 B2
• Filed: 12/06/2012
• Issued: 01/31/2017
• Est. Priority Date: 07/28/2010
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Yosui, Kuniaki
• Primary Examiner(s): Dinh, Trinh
• Application Number:
  US13/706,409
• Publication Number:
  US 20130099994A1
• Time in Patent Office: 1,517 Days
• US Class Current: 1/1
• CPC Class Codes: G06K 7/10237 the reader and the record carrier being capable of selectively switching between reader and record carrier appearance, e.g. in near field communication [NFC] devices where the NFC device may function as an RFID reader or as an RFID tag
• 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 1/2291 used in bluetooth or WI-FI devices of Wireless Local Area Networks [WLAN] H01Q1/241 takes precedence; WLAN in general H04W
• CPC Class Codes: H01Q 1/243 with built-in antennas
• 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 19/00 Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic combination of horns with slotted waveguide array H01Q13/0233
• 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: H04B 5/266 One coil at each side, e.g. with primary and secondary coils

Abstract

In an antenna apparatus, a power feed antenna includes a coil conductor and connected to a power feed circuit, a first booster conductor coupled to the coil conductor of the power feed antenna through an electromagnetic field, the first booster conductor having a planar plate shape, and a second booster conductor coupled to the first booster conductor through an electromagnetic field and coupled to the power feed antenna through an electromagnetic field. Thus, the antenna apparatus is much less influenced by nearby metallic objects and a shape of an included radiation plate may be more freely determined without requiring a highly accurate positional relationship between the radiation plate and the coil conductor.

Claims

1. An antenna apparatus comprising:

a power feed antenna including a coil conductor and connected to a power feed circuit;

a first booster conductor coupled to the coil conductor of the power feed antenna through an electromagnetic field, the first booster conductor having a planar plate shape; and

a second booster conductor coupled to the first booster conductor through an electromagnetic field and coupled to the power feed antenna through an electromagnetic field.

2. The antenna apparatus according to claim 1, wherein in plan view, a first edge portion of the coil conductor overlaps a first edge portion of the first booster conductor, a second edge portion of the coil conductor overlaps a first edge portion of the second booster conductor, and a second edge portion of the first booster conductor overlaps a second edge portion of the second booster conductor.

3. The antenna apparatus according to claim 1, wherein the first booster conductor is larger than the second booster conductor.

4. The antenna apparatus according to claim 3, wherein a distance between the power feed antenna and the first booster conductor is less than a distance between the power feed antenna and the second booster conductor.

5. The antenna apparatus according to claim 1, wherein the power feed antenna, the first booster conductor, and the second booster conductor are stacked on each other in any order.

6. The antenna apparatus according to claim 1, wherein the coil conductor is a rectangular or substantially rectangular spiral conductor located on an insulating support film.

7. The antenna apparatus according to claim 1, wherein the coil conductor includes multilayered loop conductor patterns.

8. The antenna apparatus according to claim 1, wherein each of the first booster conductor and the second booster conductor includes a conducting film located on an insulating support film.

9. The antenna apparatus according to claim 1, wherein the second booster conductor is ring-shaped and overlaps one side of the coil conductor.

10. The antenna apparatus according to claim 1, wherein the second booster conductor includes a ring portion and a linearly extending portion extending from the ring portion, and the second booster conductor overlaps the coil conductor on two sides thereof.

11. The antenna apparatus according to claim 1, wherein the second booster conductor includes a ring portion and an L-shaped or substantially L-shaped portion extending from the ring portion, and the second booster conductor overlaps the coil conductor on three sides thereof.

12. The antenna apparatus according to claim 1, further comprising a capacitor connected to both ends of the coil conductor.