Optimization of the Artificially Anisotropic Parameters in WCS-FDTD Method for Reducing Numerical Dispersion

A 3-D artificial anisotropy weakly conditionally stable finite-difference time-domain (AA-WCS-FDTD) method is presented to reduce the dispersion error without introducing additional computational cost and complexity. The motivation is to equal the speed of light in the numerical simulation to the physical speed through manipulating the permittivity and permeability. The proposed AA-WCS-FDTD algorithm achieves the reduced dispersion error for the arbitrary incident angles, different time-step sizes, and wideband frequency. The analyses of the stability and dispersion indicate that the proposed algorithm is WCS, and the Courant-Friedrich-Levy condition is slightly changed. The numerical example demonstrates that the proposed method has a reduced dispersion error and high accuracy as compared to the WCS-FDTD method.