An efficient analysis on discontinuities of lossy obstacle in axially symmetrical transmission lines using hybrid numerical method

A novel efficient numerical method, which is based on the extended spectral domain approach combined with the mode-matching method, is applied to evaluating the transmission characteristics for a axial symmetric lossy obstacle placed in a coaxial line or a circular waveguide. Since the formulation procedure utilizes the biorthogonal relation and it does not utilize any approximate perturbational scheme, the method is capable to analyze a variety of obstacles, thinner and/or thicker and wide range of conductivity in short computation time. The present method provides not only the precise analysis and design of coaxial devices including conductive and/or dielectric discontinuities, but also provides the useful tools for the accurate frequency-dependent measurement of the material´s properties. The results are compared with FEM where FEM computations are feasible, although the FEM computations cannot cover the whole performances of the present method. The good agreement is observed in the correspondent range.