Scattering parameters extraction of dielectric loaded circular waveguide using cylindrical coordinate system-based FDTD method

The scattering parameters of circular waveguide loaded with dielectric material is proposed to be extracted using a method of finite-difference time-domain (FDTD) based on cylindrical coordinate system. The extraction of scattering parameters, i.e. reflection coefficient (S₁₁) and transmission coefficient (S₂₁), are performed by the electric fields obtained on different observation planes closed to the dielectric material. Some isotropic dielectric material which partially and fully loaded circular waveguide are included in the analysis. To validate the result of FDTD method, another analysis is carried out by using finite element method (FEM) commercialized software. Furthermore, the FDTD method is also applied to analysis a circular waveguide loaded with some anisotropic dielectric material. From the result, it shows that the proposed FDTD method has a good agreement qualitatively compared to the commercialized software with some discrepancy on the extraction result less than 3% for isotropic dielectric material loaded circular waveguide. Meanwhile, there is no result comparison for anisotropic dielectric material loaded circular waveguide due to an inability of commercialized software to perform a simulation in cylindrical coordinate system.