Efficient Matrix Filling for a Volume-Surface Integral Equation Method

An efficient hybrid method is presented to solve the electromagnetic (EM) scattering from complex thin-layer composite targets. This hybrid method is the combination of volume-surface integral equation (VSIE) and equivalent dipole-moment (EDM). In this VSIE, the Rao-Wilton-Glisson (RWG) basis functions are used to expanded the surface currents on perfect electric conductor (PEC), and the simplified prism vector (SPV) basis functions are utilized to approximate the volume currents in dielectric volume. In EDM, the SPV basis-based dipole model is presented for thin dielectric volume, and the RWG basis-based dipole model is applied for PEC. The presented model improves the calculating efficiency of numerical integration part within the threshold for thin dielectric in comparison with the widely used the Schaubert-Wilton-Glisson (SWG) basis-based dipole model. Besides, the EDM significantly accelerates the filling of impedance matrix elements by avoiding dual or triple integration. Furthermore, in this hybrid method, the multilevel fast multipole algorithm (MLFMA) is utilized to accelerate the iterations. Numerical results are shown to illustrate the efficiency and accuracy of the presented method.