Rectangular waveguide diplexers with a circular waveguide common port

Design of rectangular waveguide diplexers with a circular waveguide common port is presented. Ridged H- and E-plane circular-to-rectangular-waveguide T-junctions are proposed as an optimum diplexing manifold. Full-wave optimization is used in the diplexer design. Ka-band H- and E-plane rectangular waveguide diplexers with a circular waveguide common port are designed. Measured results are in good agreement with computed results. The sensitivity of the diplexer performance with respect to the manufacturing tolerance is examined through tolerance analysis.