Meta-element antenna and array

• US 20040227667A1
• Filed: 03/02/2004
• Published: 11/18/2004
• Est. Priority Date: 05/12/2003
• Status: Active Grant

• Current Assignee: HRL Laboratories LLC (The Boeing Co.)
• Original Assignee: HRL Laboratories LLC (The Boeing Co.)
• Inventors: Sievenpiper, Daniel F.
• Granted Patent: US 7,068,234 B2
• Time in Patent Office: Days
• US Class Current: 343/700MS
• CPC Class Codes: H01Q 13/20 Non-resonant leaky-waveguide or transmission-line antennas; Equivalent structures causing radiation along the transmission path of a guided wave
• CPC Class Codes: H01Q 15/002 said selective devices being reconfigurable or tunable, e.g. using switches or diodes
• CPC Class Codes: H01Q 15/008 said selective devices having Sievenpipers' mushroom elements
• CPC Class Codes: H01Q 19/32 the primary active element being end-fed and elongated
• CPC Class Codes: H01Q 21/061 Two dimensional planar arrays
• CPC Class Codes: H01Q 23/00 Antennas with active circuits or circuit elements integrated within them or attached to them
• CPC Class Codes: H01Q 3/26 varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture H01Q3/12, H01Q3/22, H01Q3/24 take precedence
• CPC Class Codes: H01Q 3/443 varying the phase velocity along a leaky transmission line frequency scanning H01Q3/22; non-resonant leaky-waveguide or transmission-line aerials H01Q13/20
• CPC Class Codes: H01Q 3/46 Active lenses or reflecting arrays
• CPC Class Codes: H01Q 9/0442 with particular tuning means

Abstract

An antenna having at least one main element and a plurality of parasitic elements. At least some of the elements have coupling elements or devices associated with them, the coupling elements or devices being tunable to thereby control the degree of coupling between adjacent elements. Controlling the degree of coupling allows a lobe associated with the antenna to be steered.

Claims

1. An antenna comprising:

(a) at least one main element; and

(b) a plurality of parasitic elements, where at least some of the elements have coupling elements or devices associated with them, the coupling elements or devices being tunable to control a degree of coupling between adjacent elements.

2. The antenna of claim 1 wherein the coupling devices are tunable capacitors.

3. The antenna of claim 1 wherein the coupling devices have a physical size which is much smaller than a wavelength of a normal operating frequency of the antenna, so they can be described using a lumped circuit model.

4. The antenna of claim 1 wherein the elements are selected from the group consisting of metal patches, dipoles, dielectric resonators, and other resonant structures capable of storing microwave energy.

5. The antenna of claim 1 wherein the at least one main element and the plurality of parasitic elements are disposed in a two dimensional array spaced from a ground plane, the at least one main element and the plurality of parasitic elements being spaced from the ground plane by a distance no greater than one tenth of a wavelength of a normal operating frequency of the antenna.

6. The antenna of claim 5 wherein the parasitic elements are formed by an array of metal plates disposed on a dielectric medium.

7. The antenna of claim 6 wherein the coupling elements are variable capacitors.

8. The antenna of claim 7 wherein the variable capacitors are MEMS capacitors.

9. The antenna of claim 7 wherein the variable capacitors are varactors.

10. The antenna of claim 1 wherein the antenna has a plurality of said main elements with each main element having an associated group of parasitic elements and having an associated phase shifter, the associated phase shifter providing a relatively coarse lobe directional control for said antenna and the associated group of parasitic elements providing a relatively fine lobe directional control for said antenna.

11. The antenna of claim 10 wherein the plurality of main elements and the plurality of groups of parasitic elements are disposed in a two dimensional array spaced from a ground plane, the plurality of main elements and the plurality of groups of parasitic elements being spaced from the ground plane by a distance no greater than one tenth of a wavelength of a normal operating frequency of the antenna.

12. The antenna of claim 11 wherein the plurality of groups of parasitic elements are formed by a two dimensional array of conductive plates disposed on a dielectric medium.

13. The antenna of claim 12 wherein the plurality of main elements are formed by an array of elongate conductive elements, the elongate conductive elements each having a length which is longer than a maximum dimension of one of said conductive plates.

14. The antenna of claim 12 wherein the plurality of main elements are formed by an array of conductive elements, the elongate conductive elements each having outer dimensions which are approximately the same as one of said conductive plates.

15. The antenna of claim 11 wherein the coupling elements are variable capacitors.

16. The antenna of claim 15 wherein the variable capacitors are MEMS capacitors.

17. The antenna of claim 16 wherein the variable capacitors are varactors.

18. A method of steering an antenna comprising:

disposing at least one main element and a plurality of parasitic elements in an array adjacent a ground plane, where at least some of the elements have coupling elements or devices associated with them; and

adjusting the coupling elements or devices to thereby control the degree of coupling between adjacent elements in said array whereby the degree coupling varies cyclically in radial directions away from said at least one main element in said array.

19. The method of claim 18 wherein the coupling elements include variable capacitors and wherein adjusting of the coupling elements is performed by tuning the variable capacitors.

20. The method of claim 19 wherein the variable capacitors are MEMS capacitors.

21. The method of claim 19 wherein the variable capacitors are varactor diodes.

22. The method of claim 18 wherein the at least one main element and the plurality of parasitic elements are spaced from the ground plane by a distance no greater than one tenth of a wavelength of a normal operating frequency of the antenna.

23. The method of claim 22 wherein the antenna has a plurality of said main elements with each main element having an associated group of parasitic elements and having an associated phase shifter and further including

(a) adjusting the phases of the phase shifters to thereby provide a relatively coarse lobe directional control for said antenna and

(b) wherein adjusting the coupling elements or devices to thereby control the degree of coupling between adjacent elements in the groups of parasitic elements provide a relatively fine lobe directional control for said antenna.