Design and performance of an HTS beamforming network for satellite communications

A high temperature superconductor (HTS) beamforming network (BFN) is reported based on a multiple power divider technique involving a cascade of 3 dB branch-line couplers. The 1-to-4 HTS BFN was designed to operate over the frequency range of 11.7 - 12.2 GHz. Superconducting beamforming networks can offer several advantages compared to a conventional BFN, including a significant reduction in size and weight, as well as lower loss and higher sensitivity. Experimental results for the BFN show insertion losses ranging from 6.1 dB to 6.4 dB for the four output ports at the centre frequency. Return losses are better than 13 dB at the input and output ports over the 500 MHz bandwidth. The design procedure can be extended to realize an N-port BFN.