Enhanced Total-Field/Scattered-Field Technique for Isotropic-Dispersion FDTD Scheme

A new total-field/scattered-field (TF/SF) technique is proposed for the isotropic-dispersion finite difference time domain (ID-FDTD) scheme. The proposed technique does not calculate incident fields on the TF/SF boundary by using a one-dimensional (1D) FDTD scheme as is used in the conventional technique or by using a fast Fourier transform (FFT) algorithm such as is used in the analytic field propagation (AFP) method, but proceeds instead by using an analytic expression of the incident field. Hence, the proposed technique does not require the interpolation procedure that must be used to simulate an oblique incident wave in the conventional technique. To verify the effectiveness of the proposed technique, the quality of the plane waves excited by the proposed and conventional techniques are compared and discussed. Also, the accuracy of the proposed method is numerically shown in a scattering problem.