A 3-D Total-Field/Scattered-Field Plane-Wave Source for the Unconditionally Stable Associated Hermite FDTD Method

In this letter, we apply the basic principle of the total field/scattered field method to the 3-D associated Hermite unconditionally stable finite-difference time-domain (FDTD) method (AH FDTD) and achieve the plane-wave incidence for the 3-D AH FDTD method. The theory of the translation operator is introduced, and the electric and magnetic density are expressed explicitly in the AH domain. Then, the expansion coefficients of the incident plane-wave at any point are calculated using the AH translation operator and the multiple small-steps method. Numerical examples demonstrate the accuracy of the proposed method, particularly when computing a model with low-frequency or large wavelength-grid ratios.