Planar three-dimensional constrained lenses

A new design for a beamforming lens is presented. Both faces are planar arrays of radiating elements interconnected by transmission lines whose length varies as a function of radius. While the front face elements are regularly spaced, the back face elements are displaced radially from their corresponding front face elements, the amount of displacement also being a function of radius. We show that such a lens is capable of forming low sidelobe beams over an angular sector 36 beamwidths across in all planes of by switching between clusters of only seven feed elements. Because both faces are planar, construction of lightweight lenses for multibeam antennas should be feasible.