Hybrid antenna and scattering matrix based beamformer for wide-angle scanning

This paper presents a new hybrid antenna design and beamformer, which is capable of electronic scanning over hundreds of beamwidths with little degradation in the antenna pattern. The new compound hybrid antenna designs are discussed, with emphasis on one design that is composed of a planar array surrounded by polynomially-defined reflector surfaces. The ratio between the reflector aperture and array areas is compared to the theoretical limit. A new approach to beamforming in hybrid antennas is also discussed. Using a scattering matrix model for the hybrid antenna system., a bi-directional transformation is developed that relates the signals at the hybrid system feed to the signals that would be present in a planar array at the location of the reflector aperture. This allows standard planar array analysis and synthesis techniques to be used with the hybrid system. Examples are provided for transmit and receive weight synthesis.