Complying-Divergence ADE-CFS-PML for the FCC-FDTD (2, 4) Method and Its Numerical Properties

A complex-frequency-shifted perfectly matched layer (CFS-PML) for the face-centered cubic finite-difference time-domain (FCC-FDTD) method with second-order in time and fourth-order in space, termed as FCC-FDTD (2, 4), is proposed in this article. To apply the FCC-FDTD (2, 4) method in solving complex electromagnetic problems, the CFS-PML is proposed through an auxiliary differential equation (ADE), which enhances the absorbing performance and substantially simplifies the derivation of the time-marching formulations. Due to the fourth-order sampling approaches of FCC grids in space, the computational domain-absorbing boundary interface is carefully analyzed. Moreover, the proposed method exhibits complying-divergence. Then, the optimal ranges of three absorbing boundary constitutive parameters are found through the numerical sweeping method and verified by the genetic algorithm. Three numerical examples, the electromagnetic wave propagation, electromagnetic scattering of multiple targets with fine details, and the electric field distribution of a large-scale airplane, are carried out to demonstrate the performance of the proposed method. The results indicate that the developed ADE-CFS-PML absorbing boundary for the FCC-FDTD (2, 4) method shows good accuracy and stability.