The prolate and oblate spheroid perfectly matched layers

A set of flexible prolate and oblate spheroid perfectly matched layers (PMLs) is presented for more effective finite element solution of three-dimensional unbounded problems of certain geometries. The main advantage of the spheroid PMLs is that they can be easily adjusted to adapt to long or flat geometries and reduce the buffer region between a scatterer and the PML so as to increase the computational efficiency. In addition, the spheroid PMLs avoid the corner problem encountered by planar PMLs. The proposed spheroid PMLs are very suitable for FEM-PML analysis of long or flat objects.