Analysis of microstrip discontinuities using the method of integral equations for overlapping regions

Abstract

The method of integral equations for overlapping regions (MIEOR) in conjunction with a planar dispersive waveguide model is proposed for the investigation of microstrip discontinuity problems. A general formulation for a microstrip multiport junction and the numerical solution for the scattering matrix of T- and right-angled bend junctions with and without matching stubs are presented. The proposed technique directly leads to Fredholm's integral equation of the second kind or a coupled set of integral equations for the electric field components defined in overlapping subregions of the planar dispersive waveguide model. The Galerkin's method is employed to find the unknown coefficients in the electric field series expansion which represent the S-parameters of the junctions. The mathematical substantiation of the algorithm is provided. Numerical results are presented for T- and right-angled microstrip junctions showing good agreement with results already published.