High gain planar scanned antenna array

• US 20020158798A1
• Filed: 04/30/2001
• Published: 10/31/2002
• Est. Priority Date: 04/30/2001
• Status: Active Grant

• Current Assignee: IPR Licensing Incorporated (InterDigital, Inc.)
• Original Assignee: Interdigital Acquisition Corporation (InterDigital, Inc.)
• Inventors: Gainey, Kenneth M., Chiang, Bing, Snyder, Christopher A., Gothard, Griffin K.
• Granted Patent: US 6,606,057 B2
• Time in Patent Office: Days
• US Class Current: 342/372
• CPC Class Codes: H01Q 19/32 the primary active element being end-fed and elongated
• CPC Class Codes: H01Q 3/446 the radiating element being at the centre of one or more rings of auxiliary elements
• CPC Class Codes: H01Q 9/32 Vertical arrangement of element H01Q9/40 takes precedence

Abstract

An antenna array having a central active element and a plurality of passive elements surrounding the active element is disclosed. A dielectric substrate or other slow wave structure is disposed radially outwardly from the passive elements for slowing the radio frequency waves so as to increase the antenna directivity by reducing the amount of energy radiated in the elevation direction.

Claims

1. An antenna comprising:

an active element;

a plurality of passive elements spaced apart from and circumscribing said active element; and

a dielectric substrate surrounding said active element and said plurality of passive elements such that the radio frequency wave emitted by said active element in the transmitting mode or received by said active element in the receiving mode contacts said dielectric substrate thereby affecting the radiation beam pattern of said active element.

2. The antenna of claim 1 wherein the antenna directivity is increased along a longitudinal plane through the dielectric substrate.

3. The antenna of claim 1 wherein the antenna radiation is attenuated in a direction perpendicular to the dielectric substrate.

4. The antenna of claim 1 wherein the dielectric substrate is in the shape of a ring, including a circular band defining a central aperture wherein the active element and the plurality of passive elements are located within the central aperture.

5. The antenna of claim 4 wherein the boundary between the circular band and the central aperture has a taper from the top surface of the dielectric substrate toward the bottom surface of the dielectric substrate in the direction of the ring center.

6. The antenna of claim 4 wherein the outer edge of the ring has a taper from the top surface of the dielectric substrate toward the bottom surface of the dielectric substrate in the direction away from the ring center.

7. The antenna of claim 4 further comprising a ground plane oriented below the dielectric substrate, wherein the height of the dielectric substrate is a quarter-wavelength of the received or transmitted signal frequency.

8. The antenna of claim 7 wherein the received or transmitted signal frequency is the carrier frequency in a code-division multiple access system.

9. The antenna of claim 1 wherein the dielectric substrate is fabricated of a low loss dielectric material.

10. The antenna of claim 9 wherein the material is selected from the group comprising, polystyrene, alumina, polyethylene and an artificial dielectric.

11. The antenna of claim 9 wherein the dielectric of which the dielectric substrate is formed has a propagation constant less than the propagation constant of radio frequency energy in air.

12. The antenna of claim 1 further comprising a ground plane below the dielectric substrate.

13. The antenna of claim 1 wherein the active element and the plurality of passive elements are vertically oriented.

14. The antenna of claim 13 wherein the plurality of passive elements are equally spaced apart from the active element.

15. The antenna of claim 13 wherein the plurality of passive elements includes at least three passive elements.

16. The antenna of claim 13 wherein the load impedance of at least one of the plurality of passive elements is controllable.

19. The antenna of claim 18 wherein the plurality of passive elements are equi-distant from the active element.

20. The antenna of claim 18 wherein each one of the plurality of passive elements has an independently selectable impedance.

21. The antenna of claim 18 wherein the plurality of parasitic elements are arranged in one or more concentric circles extending outwardly from the active element.

22. The antenna of claim 18 wherein the parasitic elements comprising the outermost concentric circle are shorter than the parasitic elements comprising the other concentric circles.

23. The antenna of claim 18 wherein the active element, the plurality of parasitic elements and the plurality of passive elements are vertically oriented, including a ground plane, beneath and proximate to the lower end of the active element, the plurality of parasitic elements and the plurality of passive elements.

24. The antenna of claim 23 wherein the plurality of parasitic elements are formed by creating a U-shaped slot in the ground plane such that a deformable joint is defined by the slot and wherein the plurality of parasitic elements are created by bending the ground plane region defined by the U-shaped slot upwardly along the deformable joint.

25. The antenna of claim 18 wherein each one of the plurality of parasitic elements has a controllable reactance.

26. The antenna array of claim 18 wherein the antenna radiation is attenuated in a direction parallel to the plurality of parasitic elements.

28. The antenna of claim 27 wherein the plurality of mesas have unequal heights.

29. The antenna of claim 28 wherein the top surface of the innermost mesa is tapered upwardly moving away from the central aperture.

30. The antenna of claim 27 wherein the top surface of the mesas near the outer edge are tapered downwardly moving away from the central aperture.

31. The antenna of claim 27 wherein the antenna radiation is attenuated in a direction perpendicular to the slow wave structure.

17. An antenna comprising:

an active element;

a plurality of passive elements spaced apart from said active element and arranged in a circle wherein said active element is at the center thereof;

a dielectric substrate in the shape of a ring including a circular band defining an interior aperture;

wherein said antenna is operated in a first mode when said dielectric substrate is oriented such that said plurality of passive elements and said active element are disposed within the interior aperture; and

wherein said antenna operates in a second mode when said dielectric substrate is absent.

18. An antenna comprising:

an active element;

a plurality of parasitic elements spaced apart from and circumscribing said active element; and

a plurality of passive elements spaced between said active element and said plurality of parasitic elements.

27. An antenna comprising:

an active element;

a plurality of passive elements spaced apart from said active element; and

a structure in the shape of a ring including a central aperture, said structure oriented such that said plurality of passive elements are disposed within the central aperture, wherein said structure further includes a plurality of concentric mesas defining a plurality of concentric grooves there between.

32. An antenna comprising:

an active element;

a ground plane proximate the base of said active element;

a plurality of vertical parasitic elements spaced apart from said active element;

a plurality of passive elements spaced between said active element and said plurality of parasitic elements;

a dielectric substrate; and

wherein one of said plurality of passive elements and at least one of said plurality of parasitic elements are disposed on said dielectric substrate, and wherein said dielectric substrate is vertically affixed to said ground plane, and wherein said at least one parasitic element vertically affixed to said dielectric substrate is shorted to said ground plane.

33. The antenna of claim 32 comprising a plurality of dielectric substrates, wherein each one of the plurality of dielectric substrates includes one of the plurality of passive elements and at least one of the plurality of parasitic elements.

34. The antenna of claim 33 wherein each one of the plurality of dielectric substrates has a first taper on the edge proximal the active element and second taper on the edge distal the active element.