Compact Multi-Beam Forming Network with Three-way Power Divider Combined Rat-Race Coupler and Branch-Line Coupler

Demands on high-throughput communication for airplanes and ships through a high-throughput satellite using the Ka-band have increased. In Ka-band satellite communication, a multi-feeds per beam system that consists of a reflector and multiple primary feeds is widely used. A compact beam-forming network (BFN) is required in this system. We propose a compact BFN with three-way power dividers in this paper, consisting of a rate-race coupler and a branch-line coupler. We fabricated a 20 GHz-band multilayer flangeless 16-beam-forming network. As a result, the measurement and the simulated results are generally in good agreement. The BFN size is 200 (L) mm × 260 (W) mm × 150 (H) mm, and the weight is 7kg. Therefore, the compact BFN having good characteristics are realized.