New Characteristic Impedance Expression for Rigorous Study of Isotropic Waveguide

In this study, a full-wave numerical modal integral method is proposed to evaluate the characteristic impedance of symmetrical/asymmetrical finline-type structures. For this purpose, the Galerkin’s procedure was applied while using the formalism concept of mathematical operators. To successfully evaluate the accuracy of the numerical results obtained through this method, a new and efficient waveguide analytical expression, based on the transformation of the finline into an ordinary isotropic homogeneous rectangular waveguide, was introduced.