Numerical analysis of waveguide discontinuity problems using the network model decomposition method

The use of the network model decomposition method for analyzing arbitrarily shaped H- and E-plane waveguide junctions is discussed. By using the polygon discretization technique previously introduced by the author (1990), the waveguide discontinuity region, which is surrounded by a metallic wall and the reference planes chosen, is first discretized; the topological model and the corresponding network model for the waveguide discontinuity are then established. In the formulation, equivalent current sources connected to the nodes on the boundary of the region are introduced to replace the effect of the field external to the region. The field internal to the region is approximated by the nodal voltage distribution of the network model, which can then be used to determine the scattering parameters of the waveguide junction. A diakoptic algorithm for the solution of the network model is also developed. Numerical results for various H- and E-plane junctions are given, and it is shown that the method compares favorably compares with other theories