ANTENNA DEVICE

• US 20130249769A1
• Filed: 12/07/2012
• Published: 09/26/2013
• Est. Priority Date: 03/26/2012
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: KASHIWAGI, Ippei, HIGAKI, Makoto, NISHIO, Masaki
• Granted Patent: US 9,196,955 B2
• Time in Patent Office: Days
• US Class Current: 343/876
• CPC Class Codes: H01Q 1/50 Structural association of antennas with earthing switches, lead-in devices or lightning protectors
• CPC Class Codes: H01Q 21/26 Turnstile or like antennas comprising arrangements of three or more elongated elements disposed radially and symmetrically in a horizontal plane about a common centre
• CPC Class Codes: H01Q 3/24 varying the orientation by switching energy from one active radiating element to another, e.g. for beam switching
• CPC Class Codes: H01Q 9/42 with folded element, the folded parts being spaced apart a small fraction of the operating wavelength

Abstract

There is provided an antenna device including: a finite ground plane; a feeding point; feed antenna elements arranged in a radial fashion around the feeding point at a height from the finite ground plane; a selector switch to connect a first end of a feed antenna element selected from the feed antenna elements to the feeding point; and parasitic elements arranged correspondingly to the feed antenna elements, in which a first end thereof is connected to the finite ground plane and a portion including a second end thereof is capacitively coupled with the feed antenna element corresponding thereto, wherein a first length of the parasitic element is approximately a quarter of a wavelength of a radio frequency to be used, and a length from the second end of the feed antenna element to the feeding point is shorter than the first length of the parasitic element.

Claims

1. An antenna device comprising:

a finite ground plane;

a feeding point provided on the finite ground plane;

a plurality of feed antenna elements arranged in a radial fashion around the feeding point at a height from the finite ground plane;

a selector switch to connect a first end of a feed antenna element selected from the plurality of feed antenna elements to the feeding point; and

a plurality of parasitic elements arranged correspondingly to the feed antenna elements, in which first ends of the parasitic elements are connected to the finite ground plane, and portions including second ends of the parasitic elements are capacitively coupled with the feed antenna elements corresponding to the parasitic elements,

wherein a first length of each parasitic element is approximately a quarter of a wavelength of a radio frequency to be used, and

a length from the second end of each feed antenna element to the feeding point is shorter than the first length of each parasitic element.

2. The antenna device according to claim 1, wherein a distance between the feed antenna element and the parasitic element corresponding thereto is equal to or less than one tenth of the wavelength of the radio frequency to be used.

3. The antenna device according to claim 1, wherein the finite ground plane has rectangular shape and the first ends of the parasitic elements are connected to corners of the finite ground plane, respectively.

4. The antenna device according to claim 1, wherein the parasitic element is an inverted-L element.

5. The antenna device according to claim 4, wherein

the parasitic element includes a first conductive element parallel to the finite ground plane and a second conductive element a first end of which is connected to one end of the first conductive element and a second end of which is connected to the finite ground plane,

the feed antenna element corresponding to the parasitic element is parallel to the finite ground plane,

the first conductive element is arranged at a higher height than that of the feed antenna.

6. The antenna device according to claim 1, wherein

the finite ground plane has rectangular shape,

the first ends of two parasitic elements are connected to corners of the finite ground plane, the corners being adjacent to each other, and

the feeding point is arranged between the corners in the finite ground plane.

7. The antenna device according to claim 1, wherein

the selector switch selects the feed antenna element from the feed antenna elements according to a control signal given from an external.

8. The antenna device according to claim 1, wherein

the feed antenna elements are arranged at a distance approximately equal to each other.

9. The antenna device according to claim 1, wherein

the feed antenna element includes a linear-shaped conductive element.

10. The antenna device according to claim 1, wherein

the feed antenna element includes a plate-shaped conductive element.

11. The antenna device according to claim 1, wherein

the parasitic element includes a linear-shaped conductive element.

12. The antenna device according to claim 1, wherein

the parasitic element includes a plate-shaped conductive element.

13. The antenna device according to claim 1, wherein

the parasitic element includes a meander-shaped conductive element.

14. The antenna device according to claim 1, wherein

the selector switch includes a PIN (P-intrinsic-N) diode switch, a FET (Field Effect Transistor) switch, or a MEMS (Micro Electro Mechanical System) switch.