Low loss, variable phase reflect array

1. A reflect array, comprising:

a dielectric substrate having a first surface and a second surface;

a continuous conductive layer on the second surface; and

a first array of phasing elements and a second array of phasing elements interleaved in a single layer on the first surface, the elements of the first array having a first shape and the elements of the second array having a second shape different from the first shape;

wherein the first array and the second array are collectively configured to reflect an incident microwave beam in a predetermined frequency band to provide a reflected beam, the reflected beam having a phase shift relative to the incident beam that is determined, at least in part, by dimensions of the elements of both the first and second arrays of phasing elements; and

wherein a spacing between adjacent elements of the second array is substantially equal to a spacing between adjacent elements in the first array.

2. The reflect array of claim 1 , wherein the elements of the first array are “X” shapes and the elements of the second array are square patches.

3. The reflect array of claim 1 , wherein the phase shift at any point within an extent of the reflect array can be set to any value within a continuous range spanning more than 315 degrees by setting dimensions of the phasing elements in the first and second arrays.

4. The reflect array of claim 3 , wherein:

the dielectric substrate has a first curvature, and

the phase shift is varied across the reflect array to cause the reflect array to emulate a reflector having a second curvature different from the first curvature.

5. The reflect array of claim 4 , wherein:

the dielectric substrate is planar, and

the reflect array emulates a non-planar reflector.

6. The reflect array of claim 5 , wherein the reflect array emulates a curved reflector selected from the group consisting of a parabolic reflector, a spherical reflector, a cylindrical reflector, a torroidal reflector, a conic reflector, and a generalized aspheric reflector.

7. The reflect array of claim 3 , wherein the phase shift at any point within the extent of the reflect array can be set to any value within a continuous range spanning more than 355 degrees by setting the dimensions of the phasing elements in the first and second arrays.

8. The reflect array of claim 1 , wherein:

the elements of the first array are disposed on a rectangular grid, and

the elements of the second array are disposed in interstitial spaces between the elements of the first array.

9. The reflect array of claim 8 , wherein:

a spacing between adjacent rows and columns of the rectangular grid is less than a wavelength of microwave radiation in the incident microwave beam.

10. The reflect array of claim 9 , wherein:

the spacing between adjacent rows and columns of the rectangular grid is about one-half of the wavelength of the microwave radiation.

11. The reflect array of claim 8 , wherein:

the elements of the second array are disposed in the interstitial spaces along the rows and columns of the rectangular grid.

12. The reflect array of claim 1 , wherein:

for each pair of adjacent phasing elements in the first array, a single one of the phasing elements in the second array is located between those adjacent phasing elements in the first array.

13. The reflect array of claim 12 , wherein, for each phasing element in the second array that is located between adjacent phasing elements in the first array:

a first portion of that phasing element in the second array lies between portions of one neighboring phasing element in the first array; and

a second portion of that phasing element in the second array lies between portions of another neighboring phasing element in the first array.

14. A system comprising:

a microwave energy source configured to generate microwave energy in a predetermined frequency band; and

a beam director configured to direct the microwave energy received from the microwave energy source, the beam director including a reflect array, the reflect array comprising:

a dielectric substrate having a first surface and a second surface;

a continuous conductive layer on the second surface; and

a first array of phasing elements and a second array of phasing elements interleaved in a single layer on the first surface, the elements of the first array having a first shape and the elements of the second array having a second shape different from the first shape;

wherein the first array and the second array are collectively configured to reflect the microwave energy in the predetermined frequency band to provide a reflected beam, the reflected beam having a phase shift relative to the received microwave energy determined, at least in part, by dimensions of the elements of both the first and second arrays of phasing elements; and

wherein a spacing between adjacent elements of the second array is substantially equal to a spacing between adjacent elements in the first array.

15. The system of claim 14 , wherein the phase shift at any point within an extent of the reflect array can be set to any value within a continuous range spanning more than 315 degrees by setting dimensions of the phasing elements in the first and second arrays.

16. The system of claim 15 , wherein the phase shift at any point within the extent of the reflect array can be set to any value within a continuous range spanning more than 355 degrees by setting the dimensions of the phasing elements in the first and second arrays.

17. The system of claim 14 , wherein:

for each pair of adjacent phasing elements in the first array, a single one of the phasing elements in the second array is located between those adjacent phasing elements in the first array; and

for each phasing element in the second array that is located between adjacent phasing elements in the first array:

a first portion of that phasing element in the second array lies between portions of one neighboring phasing element in the first array; and

a second portion of that phasing element in the second array lies between portions of another neighboring phasing element in the first array.

18. A method comprising:

receiving microwave energy in a predetermined frequency band; and

forming the microwave energy into a reflected beam with a beam director, the beam director including a reflect array, the reflect array comprising:

a dielectric substrate having a first surface and a second surface;

a continuous conductive layer on the second surface; and

a first array of phasing elements and a second array of phasing elements interleaved in a single layer on the first surface, the elements of the first array having a first shape and the elements of the second array having a second shape different from the first shape;

wherein the first array and the second array are collectively configured to reflect the microwave energy in the predetermined frequency band to provide the reflected beam, the reflected beam having a phase shift relative to the received microwave energy determined, at least in part, by dimensions of the elements of both the first and second arrays of phasing elements; and

wherein a spacing between adjacent elements of the second array is substantially equal to a spacing between adjacent elements in the first array.

19. The method of claim 18 , wherein the phase shift at any point within an extent of the reflect array can be set to any value within a continuous range spanning more than 315 degrees by setting dimensions of the phasing elements in the first and second arrays.

20. The method of claim 19 , wherein the phase shift at any point within the extent of the reflect array can be set to any value within a continuous range spanning more than 355 degrees by setting the dimensions of the phasing elements in the first and second arrays.