New Cutoff-frequency Relations of Rectangular Waveguides Filled with Homogeneous Electric and Magnetic Anisotropic Medium

This paper proposes new analytical expressions to efficiently determine the cutoff-frequency values, especially of fundamental mode, for homogeneous electric/magnetic anisotropic rectangular waveguides (RWGs) with arbitrary transverse dimensions. To demonstrate the proposed approach, the numerical method of moments was used, involving the formalism of mathematical operators to further simplify the resolution of the boundary problems. For the purpose of validation, different types of trial functions were considered. The results obtained numerically agree closely with the results derived from the analytical expressions thus, demonstrating the efficiency of the proposed approach.