Planar Antenna

Abstract

A planar antenna includes a ground plane having a ground point. A main radiating element has a feeding point positioned adjacent to the ground point. The main radiating element is positioned adjacent to a contact side of the ground plane such that a space is formed there between. A parasitic element is positioned adjacent to the contact side such that a space is formed there between. The main radiating element has a shape such that the space between the main radiating element and the contact side becomes larger as the main radiating element becomes closer to the parasitic element and the parasitic element has a shape such that the space between the parasitic element and the contact side becomes larger as the parasitic element becomes closer to the main radiating element. Additionally, the parasitic element may have a slit formed therein.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a planar antenna according to an embodiment of the invention.

FIG. 2 is a plan view of a signal source connected to the planar antenna shown in FIG. 1.

FIG. 3 is a plan view of a planar antenna according to a comparative example.

FIG. 4 is a graph comparing the measuring properties of the planar antenna shown in FIG. 1 with the planar antenna shown in FIG. 3.

Claims

1. A planar antenna, comprising: a ground plane having a ground point;a main radiating element having a feeding point positioned adjacent to the ground point, the main radiating element being positioned adjacent to a contact side of the ground plane such that a space is formed there between; anda parasitic element positioned adjacent to the contact side of the ground plane such that a space is formed there between, the parasitic element being connected to the ground plane at a position farthest from the main radiating element, the parasitic element having at least one slit formed therein.

2. The planar antenna of claim 1, wherein the at least one slit extends substantially parallel to the contact side of the ground plane.

3. The planar antenna of claim 1, wherein the parasitic element has at least two slits of mutually different lengths.

4. The planar antenna of claim 1, wherein the planar antenna is formed in a surface of a flexible dielectric substrate.

5. The planar antenna of claim 1, wherein the planar antenna is formed within a single plane.

6. The planar antenna of claim 1, wherein the ground plane has a protruding section that substantially surrounds the feeding point of the main radiating element, the ground point being formed on the protruding section.

7. The planar antenna of claim 1, wherein the ground point contacts the contact side of the ground plane.

8. The planar antenna of claim 1, wherein main radiating element has a shape such that the space between the main radiating element and the contact side of the ground plane becomes larger as the main radiating element becomes closer to the parasitic element.

9. The planar antenna of claim 1, wherein the main radiating element is closest to the contact side in a position where the main radiating element is farthest from the parasitic element.

10. The planar antenna of claim 1, wherein the parasitic element has a shape such that the space between the parasitic element and the contact side becomes larger as the parasitic element becomes closer to the main radiating element.

11. The planar antenna of claim 1, wherein the parasitic element is closest to the contact side in a position where the parasitic element is farthest from the main radiating element.

12. A planar antenna, comprising: a ground plane having a ground point;a main radiating element having a feeding point positioned adjacent to the ground point, the main radiating element being positioned adjacent to a contact side of the ground plane such that a space is formed there between;a parasitic element positioned adjacent to the contact side of the ground plane such that a space is formed there between; andthe main radiating element having a shape such that the space between the main radiating element and the contact side of the ground plane becomes larger as the main radiating element becomes closer to the parasitic element and the parasitic element having a shape such that the space between the parasitic element and the contact side becomes larger as the parasitic element becomes closer to the main radiating element.

13. The planar antenna of claim 12, wherein the planar antenna is formed in a surface of a flexible dielectric substrate.

14. The planar antenna of claim 12, wherein the planar antenna is formed within a single plane.

15. The planar antenna of claim 12, wherein the ground plane has a protruding section that substantially surrounds the feeding point of the main radiating element, the ground point being formed on the protruding section.

16. The planar antenna of claim 12, wherein the main radiating element has an arc shaped side facing an arc shaped side of the parasitic element.

17. The planar antenna of claim 12, wherein the parasitic element has at least one slit formed therein.

18. The planar antenna of claim 17, wherein the at least one slit extends substantially parallel to the contact side of the ground plane.

19. The planar antenna of claim 17, wherein the parasitic element has at least two slits of mutually different lengths.

20. The planar antenna of claim 17, wherein the parasitic element is connected to the ground plane at a position farthest from the main radiating element.