EFFICIENT ANALYSIS OF SCATTERING FROM MULTIPLE 3-D CAVITIES BY MEANS OF A FE-BI-DDM METHOD

A finite element-boundary integral-domain decomposition method is presented for analyzing electromagnetic scattering problems involving multiple three-dimensional cavities. Specifically, the edge-based finite element method is applied inside each cavity to derive a linear system of equations associated with unknown fields. The boundary integral equation is then applied on the apertures of all the cavities to truncate the computational domain and to connect the matrix subsystem generated from each cavity. With the help of an iterative domain decomposition method, the coupling system of equations is reduced to a small one which only includes the unknowns on the apertures. To further reduce computational burdens, the multilevel fast multipole algorithm is adopted to solve the reduced system. The numerical results for the near and far fields of several selected multi-cavity problems are presented to demonstrate the validity and capability of the proposed method.