Numerical reflection of evanescent waves by PMLs: origin and interpretation in the FDTD case. Expected consequences to other finite methods

摘要

This paper shows that evanescent waves may be so strongly absorbed within perfectly matched layers (PML) that they cannot be properly sampled by discrete methods. With the finite-difference time-domain (FDTD) method, this results in a severe numerical reflection from vacuum--PML interfaces. A similar reflection also is observed with the transmission line matrix (TLM) method. The case of the finite element method (FEM) is briefly discussed in the paper.