US Patent 9722316 Horn lens antenna

An antenna includes a receiver, a horn, a lens, and an anti-reflection layer. The horn has a first end disposed on the receiver and a second end defining an aperture positioned opposite the receiver. The lens is disposed within the aperture of the horn and has a first surface facing inward toward the receiver and a second surface opposite the first surface and facing outward away from the horn. The anti-reflection layer includes a dielectric material and is disposed on the first surface of the lens. Moreover, the anti-reflection layer defines holes arranged in a 50/50 material to void ratio and that have a thickness of a quarter wavelength of a signal received by the antenna.