Generalized telegraph equations applied to nonuniform rectangular waveguides allowing hybrid mode propagation

Generalized telegraph equations are established for periodic waveguides or waveguides with nonuniform dielectric constant and variable cross section. The equations use the hybrid natural modes of the uniform periodic or dielectric waveguide. The equations are applied to a transition between a rectangular waveguide and a periodic trough-type waveguide, and some experimental results are in good agreement with theoretical predictions.