Development of a Ka-Band Non-Regular Multibeam Coverage Antenna

This article describes the development of a novel Ka-band array fed reflector antenna based on a passive multifeed-per-beam (MFPB) beamforming network (BFN) to realize multiple shaped beams for broadband satellite communications applications. The feeding array is organized in non-regular overlapped sub-arrays (OSAs) in order to generate contiguous shaped beams in two polarizations with a single reflector. The main novelty is the generation of the non-regular multibeam coverage with differently shaped beams which equalizes the traffic demand per beam as generated by a non-uniform distribution of users over the satellite coverage. The entire feeding array is organized in two interleaved and partially overlapped groups of sub-arrays, one per polarization, to better satisfy the beam overlap requirements and isolation between co-polarized beams. A complex BFN has been developed as a monolithic component through a 3-D additive manufacturing (AM) technique. The test campaign demonstrated the suitability of the design approach and the accuracy of the selected manufacturing technique for the Ka-band frequencies, with a good correlation between measured and simulated results.