INTEGRAL PML ABSORBING BOUNDARY CONDITIONS FOR THE HIGH-ORDER M24 FDTD ALGORITHM

This work demonstrates an efficient and simple PML absorbing boundary conditions (ABCs) implementation for the highorder extended-stencil M24 FDTD algorithm. To accomplish this objective, the integral forms of the PML split-field formulations were derived and discretized using the same M24 weighted multiple-loop approach, resulting in ABC performances that match the standard FDTD-based PML formulations. This proposed approach eliminates the impedance mismatches caused by switching from M24 to regular FDTD update equations within the PML regions and the necessary cumbersome subgridding implementations needed to minimize the effects of these mismatches. It also eliminates the need to use large separations between the scatterers and the PML regions as a simpler though more costly alternative. This achievement coupled with the recent effective resolution of the PEC modeling issue finally eliminates the last hurdles hindering the wide adoption of the M24 algorithm and its three-dimensional counterpart, the FV24 algorithm, as a viable option for accurate and computationally efficient modeling of electrically large structures.