Variational method of coupled strip lines with an inclined dielectric substrate

A variational method is presented for the analysis of coupled strip lines with an inclined dielectric substrate for the first time. The stationary expressions of the line capacitance matrix elements are derived based on extended spectral domain approach combined with mode-matching method (ESDMM). Numerical computations are based on Galerkin's procedure and the basis functions for the unknown aperture fields take the edge singularities into consideration. The accurate numerical values can be obtained by using a small number of basis functions.