Quasi-Optical Beamformer for Space Applications

A new quasi-optical beamformer has been developed using multi-layer printed circuit board (PCB) technology for downlink Ka-band applications in LEO Satcom. This paper presents the design and experimental validation. The beamformer effectively controls phase and amplitude to feed a linear array of 28 elements, producing 23 independent beams across a ±56° field of view. It provides low side lobe levels and achieves beam crossovers better than 3.9 dB within the 17.3–20.2 GHz band. Additionally, it ensures non-dispersive scanning in the band. The input beam ports exhibit reflection coefficients better than −10 dB across the entire band, with cross couplings below −19 dB and total insertion losses of 12.5 dB for the beamformer.