Time-Synchronized Convolutional Perfectly Matched Layer for Improved Absorbing Performance in FDTD

A performance-enhancing modification to the convolutional perfectly matched layer (CPML) technique for implementing the complex frequency-shifted perfectly matched layer (CFS-PML) absorbing boundary condition is presented. By adopting this modification, an apparent discrepancy in the time synchronization between the CPML and the main finite-difference time-domain (FDTD) algorithm is resolved. This is achieved by employing a semi-implicit approach that synchronizes CPML with the main FDTD algorithm. It is shown through 2-D and 3-D numerical examples that the suggested modification to the CPML algorithm increases its performance without increasing its computational cost.