Antenna device and communication terminal apparatus

• US 8,797,225 B2
• Filed: 09/06/2013
• Issued: 08/05/2014
• Est. Priority Date: 03/08/2011
• 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:
  US14/019,573
• Publication Number:
  US 20140009361A1
• Time in Patent Office: 333 Days
• Field of Search: 343/850, 343/860, 343/702, 343/725
• US Class Current: 343/860
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2924/19105 in a side-by-side arrangement on a common die mounting substrate
• CPC Class Codes: H01Q 1/243 with built-in antennas
• CPC Class Codes: H01Q 1/50 Structural association of antennas with earthing switches, lead-in devices or lightning protectors
• CPC Class Codes: H01Q 5/357 using a single feed point
• CPC Class Codes: H01Q 5/371 Branching current paths
• CPC Class Codes: H01Q 9/40 Element having extended radiating surface
• CPC Class Codes: H01Q 9/42 with folded element, the folded parts being spaced apart a small fraction of the operating wavelength

Abstract

An antenna device includes a plate-shaped radiating element, a frame-shaped radiating element arranged to surround the plate-shaped radiating element, and a feeding unit that includes a feeding circuit and a frequency stabilizing circuit and that is connected between the plate-shaped radiating element and the frame-shaped radiating element. The plate-shaped radiating element and the frame-shaped radiating element are connected to the feeding circuit through the frequency stabilizing circuit as a result of a first terminal portion of the frequency stabilizing circuit being connected to the frame-shaped radiating element, a second terminal portion of the frequency stabilizing circuit being connected to the plate-shaped radiating element, and a third terminal portion of the frequency stabilizing circuit being connected to the feeding circuit.

Claims

1. An antenna device comprising:

a plate-shaped radiating element;

a frame-shaped radiating element arranged to surround the plate-shaped radiating element; and

a feeding unit that includes a feeding circuit and a frequency stabilizing circuit and that is connected between the plate-shaped radiating element and the frame-shaped radiating element;

wherein

the plate-shaped radiating element and the frame-shaped radiating element are connected to the feeding circuit through the frequency stabilizing circuit as a result of a first terminal portion of the frequency stabilizing circuit being connected to the frame-shaped radiating element, a second terminal portion of the frequency stabilizing circuit being connected to the plate-shaped radiating element, and a third terminal portion of the frequency stabilizing circuit being connected to the feeding circuit.

2. The antenna device according to claim 1, wherein a portion of the frame-shaped radiating element includes a cut-out that defines a gap.

3. The antenna device according to claim 1, wherein the frequency stabilizing circuit includes a primary side reactance circuit connected to the feeding circuit and a secondary side reactance circuit coupled to the primary side reactance circuit through an electric field and/or a magnetic field.

4. The antenna device according to claim 3, wherein

the primary side reactance circuit includes a primary side series circuit including a first reactance element and a second reactance element connected in series with the first reactance element;

and

the secondary side reactance circuit includes a secondary side series circuit including a third reactance element coupled to the first reactance element and a fourth reactance element connected in series with the third reactance element and coupled to the second reactance element.

5. The antenna device according to claim 4, wherein the first reactance element and the second reactance element are coupled to each other in an opposite-phase mode, and the third reactance element and the fourth reactance element are coupled to each other in an opposite-phase mode.

6. The antenna device according to claim 4, wherein the first reactance element and the third reactance element are coupled to each other in an opposite-phase mode, and the second reactance element and the fourth reactance element are coupled to each other in an opposite-phase mode.

7. The antenna device according to claim 4, wherein the first reactance element and the third reactance element are coupled to each other in an in-phase mode, and the second reactance element and the fourth reactance element are coupled to each other in an in-phase mode.

8. The antenna device according to claim 4, wherein each of the first, second, third, and fourth reactance elements is an inductance element.

9. A communication terminal apparatus comprising:

a plate-shaped radiating element arranged within a casing;

a frame-shaped radiating element arranged along an inner side surface or an outer side surface of the casing to surround the plate-shaped radiating element; and

a feeding unit that includes a feeding circuit and a frequency stabilizing circuit and that is connected between the plate-shaped radiating element and the frame-shaped radiating element;

wherein

the plate-shaped radiating element and the frame-shaped radiating element are connected to the feeding circuit through the frequency stabilizing circuit as a result of a first terminal portion of the frequency stabilizing circuit being connected to the frame-shaped radiating element, a second terminal portion of the frequency stabilizing circuit being connected to the plate-shaped radiating element, and a third terminal portion of the frequency stabilizing circuit being connected to the feeding circuit.

10. The communication terminal apparatus according to claim 9, wherein a portion of the frame-shaped radiating element includes a cut-out that defines a gap.

11. The communication terminal apparatus according to claim 9, wherein the frequency stabilizing circuit includes a primary side reactance circuit connected to the feeding circuit and a secondary side reactance circuit coupled to the primary side reactance circuit through an electric field and/or a magnetic field.

12. The communication terminal apparatus according to claim 11, wherein

the primary side reactance circuit includes a primary side series circuit including a first reactance element and a second reactance element connected in series with the first reactance element;

and

the secondary side reactance circuit includes a secondary side series circuit including a third reactance element coupled to the first reactance element and a fourth reactance element connected in series with the third reactance element and coupled to the second reactance element.

13. The communication terminal apparatus according to claim 12, wherein the first reactance element and the second reactance element are coupled to each other in an opposite-phase mode, and the third reactance element and the fourth reactance element are coupled to each other in an opposite-phase mode.

14. The communication terminal apparatus according to claim 12, wherein the first reactance element and the third reactance element are coupled to each other in an opposite-phase mode, and the second reactance element and the fourth reactance element are coupled to each other in an opposite-phase mode.

15. The communication terminal apparatus according to claim 12, wherein the first reactance element and the third reactance element are coupled to each other in an in-phase mode, and the second reactance element and the fourth reactance element are coupled to each other in an in-phase mode.

16. The communication terminal apparatus according to claim 12, wherein each of the first, second, third, and fourth reactance elements is an inductance element.