Resonant conductance of inclined slots in the narrow wall of a rectangular waveguide

A method to determine the admittance and resonant length of an inclined slot in the narrow wall of a rectangular waveguide is presented. An expression for the admittance of the slot is derived using an angular spectrum of planewaves and the discontinuity in modal current. When the depth of cut in the top and bottom wall is assumed to be zero, the expression for resonant conductance found by the present method is exactly the same as that obtained by Stevenson. Comparison between the theoretical and experimental results on the variation of resonant conductance with angle of inclination of slots for a fixed depth of cut of 3.5 mm is presented.