A hybrid FDTD and leapfrog ADI-FDTD method with PML implementation

In this paper, a hybrid FDTD and leapfrog alternating-direction-implicit finite-difference time-domain (ADI-FDTD) method is presented. The perfectly matched layer (PML) absorbing boundary conditions are also incorporated in the method and non-uniform grids are deployed to efficiently model electromagnetic radiation and scattering in open domains. In the proposed hybridization method, the leapfrog ADI-FDTD is applied to regions of fine grids, while the FDTD is applied to regions of coarse grids. As a result, a single relatively large time step can be used uniformly over a complete solution domain; this yields a significant CPU time reduction in comparison with the conventional FDTD while maintaining accuracy with fine grid regions. The effectiveness and efficiency of the proposed hybrid method are validated and evaluated with numerical results.