A Convolutional Perfect Matched Layer (CPML) for One-Step Leapfrog ADI-FDTD Method and Its Applications to EMC Problems

A new convolutional perfectly matched layer (CPML) is proposed and implemented in one-step leapfrog alternately direction-implicit finite-difference time-domain (ADI-FDTD) method. Different from the previous developed perfectly matched layers (PMLs) used in the ADI-FDTD methods, the proposed PML has the same form as that used for the conventional FDTD method, requiring only one-step computations of the CPML auxiliary quantities. Stability of the proposed CPML is verified semianalytically and its high absorption efficiency is proven numerically. The proposed CPML is then applied to a number of applications; they include radiation generated by a current source in free space, propagating and evanescent modes in a rectangular waveguide, and transient current prediction on an aircraft that is modeled with a numerical grid of 402 x 48 x 262. Accurate results have been obtained in comparison with the results obtained with the other methods.