Multi-beam Phased-array Antenna Beamformers

A Novel Multibeam Phased Array Beamformer technology development is described suitable for Transformational Communications applications. The beamformer is being designed for Advanced SHF/EHF satellite downlink and uplink payloads and creates simultaneous high gain pencil beams feeding a planar array of 2,000 or more elements from geostationary earth orbit. The beamformer uses column and row two dimensional Rotman lens stacks feeding sub arrays of contiguous elements arranged in an equilateral triangular element lattice to minimize the number of elements and hence passive and active components needed. Radiating sub array elements each can have phase shifters for beam fine steering and shaping within the equilateral triangular beam lattice of the Rotman lens stacks capable of covering the entire 17.4º earth disc with 1200 to 2000 narrow “pixel” beams. At each beam port of the Rotman lens stack, a narrow pencil beam is formed that has frequency independent beam pointing angle due to the true time delay nature of the Rotman lens phase excitation creation. Pixel beams are combined, steered and shaped within the RF Beam switch/combiner matrix resulting in a minimum of 64 simultaneous independent communication beams. Demonstration of an active EHF array column is proposed for risk reduction in Phase II.