Development of the CPML for four-stages split-step unconditionally-stable FDTD method

An unconditionally-stable four-stages split-step convolutional perfectly matched layer (PML) algorithm is presented for modeling open region finite-difference time-domain (FDTD) applications. In the proposed method, the Maxwell's matrix is separated into four sub-matrices. Accordingly, the time step is divided into four sub-steps. Then, the formulation of the proposed method is derived. Furthermore, numerical results are carried out at different positions for different Courant-Friedrichs-Lewy numbers in two-dimensional domains, which shown that the formulation is both accurate and unconditionally-stable.