Directive beaming with lens-like superstates for low profile Fabry-Perot cavity antennas

Abstract

Lens-like superstrates designed to exhibit a spatial reflectivity map are studied for use as the partially reflecting surface in Fabry-Perot cavity antennas. Profile reduction is obtained by using only a single dielectric layer of such surfaces which is found to provide improved performance than the multi-layered superstrates. The use of such surfaces results in a varied reflectivity within the cavity and makes the boresight emissions spatially coherent. This provides high boresight directivity with improved bandwidth characteristics. With this surface as super-strate of a resonant cavity antenna, performance is evaluated for a single feed exciting the cavity. Highly directive beams with 17.6dBi peak directivity and fairly suppressed side lobes are obtained over a very wide bandwidth with only a single layer lens-like surface.