Antenna device

Patent metadata

Field	Value
Publication number	US-11081799-B2
Application number	US-201916287367-A
Country	US
Kind code	B2
Filing date	Feb 27, 2019
Priority date	Nov 29, 2016
Publication date	Aug 3, 2021
Grant date	Aug 3, 2021

Abstract

An antenna device is provided that can be designed easily and includes a flat antenna of which communication characteristics do not change significantly even when there exist metallic objects or the like in the surroundings. Moreover, the flat antenna is provided with an antenna-side signal line path conductor, an antenna-side first ground conductor, a matching circuit part, and an antenna-side connector part which are provided in an antenna-side insulator. The antenna device further includes a signal transmission cable that is provided with a radiation area setting part in the vicinity of a cable-side connector part. The antenna device is designed such that, by connecting the antenna-side connector part and the cable-side connector part to each other, substantially the entire surface of the flat antenna serves as a radiation part that radiates electromagnetic waves.

First claim

The invention claimed is:

1. An antenna device comprising:
a flat antenna comprising:
an antenna-side insulator that has a flat shape;
an antenna-side signal line path conductor that is disposed on the antenna-side insulator;
an antenna-side first ground conductor that is disposed on the antenna-side insulator along the antenna-side signal line path conductor, the antenna-side first ground conductor being arranged at a distance from the antenna-side signal line path conductor; and
a matching circuit that matches an impedance of the antenna-side signal line path conductor to an impedance of the antenna-side first ground conductor;

a signal transmission cable comprising:
a cable-side insulator;
a cable-side signal line path conductor that is disposed along a longitudinal direction of the cable-side insulator and has a first end connected to a power feeding circuit; and
a cable-side ground conductor that is arranged at a distance from the cable-side signal line path conductor and has a first end connected to a ground; and

a radiation area setting member disposed in a signal path from the signal transmission cable to the flat antenna, the radiation area setting member configured to demarcate the flat antenna as a radiation area and to set a signal path in the signal transmission cable as a non-radiation area,
wherein, in the antenna-side insulator, the antenna-side signal line path conductor is disposed to face the antenna-side first ground conductor at a predetermined interval therefrom,
wherein the signal transmission cable is a coaxial cable, and
wherein the radiation area setting member is a magnetic member.

2. The antenna device according to claim 1 ,
wherein the cable-side signal line path conductor is electrically connected to the antenna-side signal line path conductor,
wherein the cable-side ground conductor is electrically connected to the antenna-side first ground conductor, and
wherein the radiation area setting member covers at least a portion of the cable-side ground conductor.

3. The antenna device according to claim 1 ,
wherein the radiation area setting member comprises a balanced-to-unbalanced transformer,
wherein a balanced terminal of the balanced-to-unbalanced transformer is connected to each of the antenna-side signal line path conductor and the antenna-side first ground conductor, and
wherein an unbalanced terminal of the balanced-to-unbalanced transformer is connected to each of the cable-side signal line path conductor and the cable-side ground conductor.

4. The antenna device according to claim 1 , further comprising:
an antenna-side second ground conductor that is disposed on the antenna-side insulator along the antenna-side signal line path conductor, with the antenna-side second ground conductor being arranged at a distance from the antenna-side signal line path conductor, a first end of the antenna-side second ground conductor connected to the matching circuit, and a second end of the antenna-side second ground conductor connected to a ground line path,
wherein the antenna-side first ground conductor faces the antenna-side signal line path conductor in a thickness direction on a side of a principal surface of the antenna-side signal line path conductor.

5. The antenna device according to claim 1 ,
wherein the antenna-side first ground conductor faces the antenna-side signal line path conductor in a thickness direction on a principal surface of the antenna-side signal line path conductor, and
wherein the antenna device further comprises an antenna-side second ground conductor on another principal surface of the antenna-side signal line path conductor, with the antenna-side second ground conductor facing the antenna-side signal line path conductor in the thickness direction along the antenna-side signal line path conductor.

6. The antenna device according to claim 4 , wherein the antenna-side first ground conductor is electrically connected to the antenna-side second ground conductor by an interlayer connection conductor disposed on the antenna-side insulator.

7. The antenna device according to claim 4 , wherein the antenna-side second ground conductor comprises a plurality of openings that face the antenna-side signal line path conductor in the thickness direction along the longitudinal direction of the antenna-side signal line path conductor.

8. The antenna device according to claim 1 , wherein the matching circuit comprises:
a capacitance part that is disposed between the antenna-side signal line path conductor and the antenna-side first ground conductor; and
an inductance part that is disposed on the antenna-side signal line path conductor.

9. The antenna device according to claim 8 , wherein the antenna-side first ground conductor comprises an opening or a cutout in an area that faces the conductance part of the matching circuit in the thickness direction.

10. The antenna device according to claim 1 , wherein the antenna-side first ground conductor is adjacent to the antenna-side signal line path conductor in a width direction to sandwich the antenna-side signal line path conductor therebetween.

11. The antenna device according to any one of claim 1 ,
wherein the antenna-side first ground conductor faces the antenna-side signal line path conductor in a thickness direction on a first principal surface of the antenna-side signal line path conductor, and
wherein the antenna device further comprises an antenna-side second ground conductor adjacent to the antenna-side signal line path conductor in a width direction to sandwich the antenna-side signal line path conductor therebetween.

12. The antenna device according to claim 11 , wherein the antenna-side first ground conductor comprises a plurality of openings that face the antenna-side signal line path conductor in the thickness direction along a longitudinal direction of the antenna-side signal line path conductor.

13. The antenna device according to claim 1 , wherein the antenna-side insulator comprises a laminated structure having a plurality of insulating layers.

14. The antenna device according to claim 1 , wherein a radiation part of the flat antenna comprises a meandering shape.

15. The antenna device according to claim 1 , wherein the antenna-side insulator has a band-like shape along the antenna-side signal line path conductor.

16. The antenna device according to claim 1 ,
wherein the antenna-side insulator comprises a substantially flat face that has predetermined broadening, and
wherein the antenna-side signal line path conductor is disposed on the antenna-side insulator and has one of a meandering shape or a spiral shape.

17. The antenna device according to claim 16 ,
wherein the antenna device comprises at least two flat antennas that each include the antenna-side insulator, the antenna-side signal line path conductor, the antenna-side first ground conductor, and the matching circuit,
wherein pattern shapes of the antenna-side signal line path conductors in the flat antennas are arranged to avoid overlapping each other.

18. The antenna device according to claim 17 , wherein a high frequency signal from the power feeding circuit to each of the flat antennas is switched therebetween every predetermined time period.

19. The antenna device according to claim 3 , wherein the radiation area setting member comprises one of a balanced-to-unbalanced transformer of a wire-wound transformer type, a merchant type, or a lumped-parameter type.

20. An electronic instrument comprising:
a housing;
a

Assignees

• Murata Manufacturing Co

Inventors

• Kato Noboru
• Ozawa Masahiro

Classifications

• H03H7/00

  Multiple-port networks comprising only passive electrical elements as network components · CPC title

• H01Q11/02

  Non-resonant antennas, e.g. travelling-wave antenna (Yagi antennas H01Q19/30) · CPC title

• H01P3/085

  Triplate lines · CPC title

• H01Q3/24

  varying the orientation by switching energy from one active radiating element to another, e.g. for beam switching · CPC title

• H01Q5/35

  using two or more simultaneously fed points · CPC title