An Efficient 3-D Hybrid Finite Element Spectral Integral Method for Electromagnetic Problems With Interior and Exterior Spherical Boundaries

This study introduces an innovative and effective finite element spectral integral (FESI) method that combines the finite element and spectral integral methods for electromagnetic problems with interior and exterior spherical boundaries. The proposed FESI method is suitable for inhomogeneous media in an unbounded exterior homogeneous background medium and a bounded interior region. Unlike the conventional perfectly matched layer (PML) for the radiation boundary condition, our scheme not only accommodates the exact radiation condition in interior domains but also exhibits promising capabilities for achieving high accuracy and efficiency in both near-field and far-field calculations. In a series of practical illustrations, we showcase that our approach delivers markedly enhanced efficiency and reduced memory utilization over the PML method while providing a high level of accuracy.