Three-dimensional analysis of electromagnetic fields in rectangular waveguides by the boundary integral equation method

A rapidly convergent expression of electromagnetic fields in rectangular waveguides is proposed for three-dimensional electromagnetic field analysis by using the integral equation method. The new method is an improved image expansion method utilizing the rapid convergence of the orthogonal expansion method. By this new method, the slow convergence of the orthogonal method with currents near an observation point can be removed completely. In order to investigate the adequacy of the new expression, the fields produced by the line electric and magnetic current segments are calculated and compared with the values obtained by the orthogonal expansion method. This confirms that the new expression gives accurate numerical values with a short computing time. Electromagnetic fields in a rectangular waveguide with circular metallic and dielectric posts are analyzed by using the new expression. From computed values, equivalent circuits of the metallic and dielectric post are obtained and compared with values obtained by N. Marcuvitz (1951). Reasonably good agreement is obtained