Fully coupled multi-hybrid FEM-PO/PTD-UTD method for the analysis of radiation problems

A multi-hybrid method combining the finite element method (FEM) and several high frequency techniques (HFTs) for the efficient analysis of the radiation and scattering of electromagnetic waves on complex three-dimensional environments is presented. It makes use of FEM for the regions with small and complex features and one or several HFTs for the analysis of the electrically large objects of the structure. The hybridization is done in a fully-coupled way taking into account mutual interactions between the FEM domains and the objects analyzed with HFTs. Two main HFTs are used: physical optics (PO) and the uniform theory of diffraction (UTD) in order to take advantage of the use of distributed and point sources. Physical theory of diffraction (PTD) is also used when needed in order to improve the accuracy of PO. Index Terms--Electromagnetic coupling, finite element method (FEM), hybrid solution methods, physical optics (PO), physical theory of diffraction (PTD), uniform theory of diffraction (UTD).