| In this article, we use the surface integral equation theory as the theoretical foundation, method of moments as numerical method. Owing to its impedance matrix is not diagonally dominant, PMCHW (Poggio-Miller-Chang-Harrington-Wu) requires much more iterations, particularly when dealing with the electrically large problems. So in this article, a new combined field integral equation is proposed to analyze electromagnetic scattering for composite conducting and dielectric object, and the resultant matrix equation with the Galerkin type method achieves better convergence properties and this formulation is known to be free of interior resonance corruption. At the same time, the rigorous modeling of electromagnetic scattering for composite conducting and dielectric object is studied in this dissertation, and which is discussed that the equivalent surface currents vanish or not and how to orient the RWG vector basis functions by enforcing the electromagnetic boundary conditions on interfaces or at junctions. Finally, a series of numerical examples are presented to show that the proposed method are efficient and validate in dealing with composite conducting and dielectric object and can greatly improve the convergence rate.At the same time, in this article, fast multipole method is employed to speed up the matrix-vector multiplication in the iterative solution of the MoM matrix equation. By using Multilevel Fast Multipole Algorithm (MLFMA), the computational complexity can be reduced from O(N3) to O(N log N) and memory requirements can also be reduced from O(N2) to O(N log N), which not only improve the calculation efficiency of the method of moments but also reduce memory requirements. In addition, in this article, the Multilevel Fast Multipole Algorithm is paralleled to makes it possible to analyse electromagnetic scattering for arbitrarily-shaped electrically-large complex targets. |
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