Channel multiplexers for broadcasting satellite transponders in the 12 GHz band

This paper describes the development and design of waveguide manifold-type multiplexers for high-power broadcasting satellite transponders in the 12 GHz band. The input multiplexer consists of eight-pole canonical dual-mode filters with an orthomode T-shaped junction suitable for waveguide manifolds in order to provide a large amount of reflection at the adjacent channels. The measured results show that the attenuations at the adjacent channel edges are 40 dB and the insertion losses at each channel center frequency are 1.5 dB. The output multiplexer consists of four-pole longitudinal dual-mode filters.