Application of a ´Zwischenmedium´ to the radiation from a flanged waveguide

The range of application of the orthogonal expansion for solving boundary-value problems is considerably extended by introducing a suitable `Zwischenmedium¿. The radiation problem considered in this paper is solved using a cylindrical `Zwischenmedium¿. Field matching on the surface of the `Zwischenmedium¿ leads to an infinite system of linear equations for the unknown coefficients of the field expansions. The simple analytic formulation and the numerical efficiency are the essential advantages of this technique. The computed results are in good agreement with those already published.