Single-layer wide angle impedance matching (WAIM)

1. An antenna comprising:

an aperture having a plurality of antenna elements operable to radiating radio-frequency (RF) energy; and

a single-layer wide angle impedance matching (WAIM) structure coupled to and separate from the plurality of antenna elements of the aperture to provide impedance matching between the antenna aperture and free space, wherein the single-layer WAIM structure comprises a capacitive impedance surface with a two-dimensional (2D) array of sub-wavelength elements that comprises a 2D array of capacitive pieces of material.

2. The antenna of claim 1 wherein the 2D array of capacitive pieces of material comprises a 2D array of capacitive patches.

3. The antenna of claim 2 wherein the capacitive patches are square-shaped patches.

4. The antenna of claim 2 wherein the capacitive patches are hexagonal-shaped patches.

5. The antenna of claim 1 wherein the single-layer WAIM structure comprises a substrate and the sub-wavelength elements of the single-layer WAIM structure are screen printed on the substrate.

6. The antenna of claim 1 wherein the single-layer WAIM structure is separated from the aperture by at least a dielectric spacer.

7. The antenna of claim 6 wherein impedance of the single-layer WAIM structure is based on physical dimensions of its features and its surrounding medium.

8. The antenna of claim 1 wherein impedance of the single-layer WAIM structure is a function of scan angle and polarization of a propagating wave and is independent of a scan plane of the antenna.

9. The antenna of claim 1 wherein the single-layer WAIM structure has rotational symmetry.

10. The antenna of claim 1 wherein the aperture comprises a metasurface.

11. An antenna comprising:

a metasurface having a plurality of antenna elements operable to radiating radio- frequency (RF) energy; and

a single-layer wide angle impedance matching (WAIM) structure coupled to the aperture to provide impedance matching between the antenna aperture and free space, the single-layer WAIM structure having a capacitive impedance surface with a two-dimensional (2D) array of sub-wavelength elements, wherein impedance of the single-layer WAIM structure is a function of scan angle and polarization of a propagating wave and is independent of a scan plane of the antenna.

12. The antenna of claim 11 wherein the sub-wavelength elements comprises a 2D array of capacitive patches.

13. The antenna of claim 12 wherein the capacitive patches are square-shaped patches or hexagonal-shaped patches.

14. The antenna of claim 11 wherein the sub-wavelength elements are split-ring resonators or dipoles.

15. The antenna of claim 11 wherein the single-layer WAIM structure comprises a substrate and the sub-wavelength elements of the single-layer WAIM structure are screen printed on the substrate.

16. The antenna of claim 11 wherein the single-layer WAIM structure is separated from the aperture by at least a dielectric spacer.

17. The antenna of claim 16 wherein impedance of the single-layer WAIM structure is based on physical dimensions of its features and its surrounding medium.

18. An antenna comprising:

a metasurface having a plurality of antenna elements operable to radiating radio- frequency (RF) energy;

a dielectric layer coupled to the metasurface; and

a single-layer wide angle impedance matching (WAIM) structure coupled to the dielectric layer to provide impedance matching between the antenna aperture and free space, wherein single-layer WAIM structure comprise a substrate with a two-dimensional (2D) array of capacitive elements screen printed thereon, wherein impedance of the single-layer WAIM structure is a function of scan angle and polarization of a propagating wave and is independent of a scan plane of the antenna.