Design of double-ridged rectangular waveguide of arbitrary aspect ratio and ridge height

The dominant mode characteristics of a double-ridged rectangular waveguide with arbitrary values of ridge height and aspect ratio are investigated, by first determining the parameters of an equivalent single-ridged waveguide and then using the transverse resonance technique. The shunt susceptance occurring between the central ridge and the waveguide is calculated from the step susceptance formula of Marcuvitz (1951). Design curves for arbitrary values of ridge width, ridge height and aspect ratio are presented. Results are compared with the corresponding results based on a thin capacitive diaphragm model and with results obtained from an integral equation solution