Abstract: We developed an optimal perfectly matched layer method for scattering from cavity under both TM and TE polarizations by choosing a particular absorbing function with unbounded integral. The unbounded computational domain is truncated to a bounded one by using a rectangular perfectly matched layer at the open aperture. The thickness of PML is not very large in this method. Especially when the cavity opening is very large, the amount of calculations is saved and the operation sp eed is improved by usingrectangular perfectly matched layer instead of semicircle.Numerical experiments demonstrate that the optimal PML method is efficientand accurate to solve cavity scattering problems.

Key words: optimal perfectly matched layer method, TM polarization, TE polarization, electromagnetic scatteringfrom cavities