Radial Perfectly Matched Layer for the ADI-FDTD Method

In this letter, a circular absorbing boundary using the radial perfectly matched layer (RPML) is investigated for the alternating-direction-implicit finite-difference time-domain (ADI-FDTD) method. A staircase approach is used to approximate the circular boundary so that it is directly compatible with the commonly used Yee's lattice. The proposed RPML boundary is computationally more efficient than the traditional rectangular PML boundary. It was found that more than 20% of the memory and computation time can be saved by using the proposed method.