Novel Integral Equation Formulation for the Analysis of Capacitive Step Discontinuities

In this contribution, a novel integral equation formulation is used for the electromagnetic analysis of rectangular waveguide capacitive discontinuities. The proposed integral equation, solved by the Method of Moments (MoM), accurately models the coupling between the step discontinuity and a given number of arbitrarily shaped metallic posts in its vicinity. The kernel of the Integral Equation is written in terms of parallel plate Green's Functions in the spatial-spectral frequency domain taking into account the capacitive symmetry and thus reducing a 3D problem to a simpler 2.5D one. The computational technique has been validated through the analysis of a practical lowpass filter, that uses one capacitive step as an impedance inverter. The results are in very good agreement with respect of full-wave software tools while exhibiting higher computational efficiency.