The calculation of the equivalent circuit of an axially unsymmetrical waveguide junction

The parameters of the equivalent circuit of an axially unsymmetrical waveguide junction may be calculated by a direct application of the variational method developed by Schwinger. Certain useful properties of this method exist only when the junction has a certain degree of symmetry. A modification to the method by which these properties are retained even when the junction is asymmetrical is developed and shown to be closely related to the Weissfloch method for the experimental determination of the equivalent-circuit parameters. The method is illustrated by numerical calculations for the junction between an empty waveguide and one partially filled with dielectric: good agreement is found with experimental results.