Dual-Mode Waveguide Cavity Filters and Diplexer With Fractional Bandwidths Around 0.2%

This work presents the design of a low-loss narrowband waveguide diplexer for S-band satellite communication links. The design of ultra-narrowband (Δ around 0.2%) filters will be discussed as well as their applications to diplexer design. The fabricated diplexer exhibits a low-loss performance (max 1.3 dB and 1.8 dB insertion loss in each channel), and it is suited for channelizing narrow-band signals transmitted from geostationary satellites.