Concept study of a multiple beam lens antenna with an internal phase shift mask

A new antenna architecture has been investigated to assess its usefulness for limited scan systems. It consists of a passive lens with a few small subarrays spaced evenly across its focal surface. Between the lens and the focal surface is a phase shift layer, or mask, comprised of oppositely-facing planar arrays interconnected by phase shifters (similiar to a phased array lens). The mask redirects a focusing wave from an arbitrary angle onto one of the subarrays. It is shown that a system with only 19 small subarrays, and a mask containing about 4500 elements could provide complete Earth coverage with as many as 19 simultaneous 0.3 deg beams. The pattern quality of those beams is good, provided that no two are steered to within a few beamwidths of each other.