Two-Degree-of-Freedom Linear and Planar Mircowave Array Lenses,

Abstract : A new design of beamforming lens is presented. Both faces are planar arrays of microwave or millimeter wave antenna elements, interconnected by transmission lines (as in a 'bootlace' lens) whose length vary as a function of radius. While the front face elements are regularly space, the back face elements are displaced radially from their corresponding front face elements, the amount of displacement also being a function of radius. Such a lens is shown to be capable of forming low sidelobe pencil beams over a solid angle of + or - 25 deg or more by switching between clusters of only seven feed elements. Because both faces are planar, construction of extremely lightweight lenses for large-aperture and/or multiple-beam antennas is feasible. Keywords include: Microwave lens, Lens antennas, Multiple-beam antennas, Electronically scanned antenna, and Low sidelobe antennas.