Perturbation Solution for Anisotropic Circular Waveguides Loaded With Eccentric Rods

A perturbation method is developed for the analysis of anisotropic circular waveguides partially filled with eccentric cylinders. The method allows to compute axial wavenumbers and field patterns for hybrid modes supported in waveguides with small eccentricities via a perturbation series. The proposed method is validated against analytical results and numerical results based on the finite-element method (FEM) and the finite-integration technique (FIT) in different configurations. The results show that the presented approach can solve, for example, the longitudinal wavenumbers of anisotropic waveguides with an eccentricity of 23% with a relative error less than 1.78% at a much lower computational cost when compared to numerical techniques.