Abstract
The dispersion relation of the hybrid modes of a rectangular waveguide with two arbitrarily placed asymmetric double ridges and the five gap and trough regions filled with dielectrics of different permittivities has been determined using the Ritz-Galerkin technique. At cut-off the general characteristic equation splits into two decoupled eigenvalue equations the solutions of which yield the H- and E-type cut-off wavelengths. Some typical numerical data on the cut-off wavelength and bandwidth of the dominant hybrid modes of nine different symmetric inhomogeneous ridged structures loaded with one dielectric are presented to illustrate their characteristics. The dispersion characteristics of a particular configuration, similar to fin-lines with thick fins, are also determined and compared with the published data.