Abstract: The transverse iris of a rectangular waveguide is analyzed by the full wave technique, and combined with the design theory of the filter, the iris is equivalent to an impedance inverter, whose parameter is obtained by full wave analysis, and then a transcendental equation is established by equaling the inverter parameter obtained by the filer synthesis theory with the former. The dimension of the iris can be obtained by solving the equation. The relation between iriss dimension and bandwidth of the band-pass filter is analyzed, which can be of constructive significance in the choice of iris structure for the filter design. Adjustments of the dimension of the designed filter are a voided, and the design is more efficient and more rigorous. Finally, several waveguide band-pass filters are designed based on a half-wave resonance cavity model, and the design values agree well with those of the emulator and experiment.

Key words: filter design, full-wave analysis, impedance inverter, iris dimension