A fast technique is desired for estimating reflection coefficients of electromagnetic planewaves from a plane boundary of discretized perfect matched layer(PML), because in thefinite element analysis(FEA) division of PML region into finite-elements and absorptionparameter distribution in the PML should be determined for achieving non-reflection fromPML boundary. For tackling this problem, we present the reflection coefficients calculatedfrom discretized wavenumber. In this paper, we consider the plane wave scattering froma PML plane boundary, and demonstrate that the results give satisfactory approximationof FEA results
