Long-time behavior of PML absorbing boundaries for layered periodic structures

In this work we consider a special case of the Perfectly Matched Layer (PML) divergence which is observed by the simulation of the planar periodic structures such as photonic crystal slabs or antenna arrays This divergence is caused by an excitation of long-living artefact evanescent waves in these structures by an incident external pulse We study the application of the known remedies to this problem increasing the distance between the structure and PML, employing the K parameter employing non-PML absorbers We also suggest a new simple and effective solution where the usual PML is backed by an additional absorbing layer (C) 2010 Elsevier BV All rights reserved