Numerical Simulation Of Electromagnetic Scattering From Dielectric And Metallic Target Using Volume-Surface Integral Equation

The modeling of the electromagnetic scattering from three-dimensional (3-D) object has been studied extensively in recent years. The interest in this subject is due to the fact that its important role in both theory study and practical applications. The scattering from the electrically large object in the complex environment has been investigated in this paper using numerical techniques. For forward approaches, corresponding integral equations are implemented according to the scenarios, then by Method of Moments (MoM), the integral equations are converted to matrix form. However, as the electrical size of the object increases, the computation complexity and memory requirement of MoM increases correspondingly. Therefore, fast algorithms such as multilevel UV decomposition method (MLUV), adaptive cross approximation (ACA) and characteristic basis function method (CBFM) are studied to address this issue.The main content of this paper includes the following parts:1. The modeling of the electromagnetic scattering from the composite3-D perfect electric conductor (PEC) or dielectric target and rough surface combined model. The Poggio, Miller, Chang, Harrington, Wu and Tsai (PMCHWT) integral equations, electric field integral equation (EFIE) are implemented on the surfaces of the dielectric and PEC objects respectively, In order to fast fill-in the impedace matrix elements resulted from operator-K, ACA is incorporated to address the issue. The bistatic radar cross sections (Bi-RCS) are calculated and analyzed.2. The modeling of the electromagnetic scattering from the Anisotropic coated object. The volume integral equation (VIE) and electric field integral equation (EFIE) are implemented in the body of the anisotropic object and the surface of the PEC object respectively. PIL OCT-TREE based ACA method is used to accelerate the calculation. The bistatic radar cross sections (Bi-RCS) are calculated and analyzed. 3. A parallel implementation of the Multilevel Characteristic Basis Function Method (MLCBFM) for the analysis of the scattering from electrically large rough surfaces is proposed. The Multilevel Characteristic Basis Function method is a direct solver, which addresses the issues of high computation burden and memory requirement without the concern of the convergence problem in iterative method. In particular, the MLCBFM is very well suited for parallelization and is parallelized using MPICH2.4. The geometric parameters of a electrically large square above a rough surface are reconstructed by means of support vector machine (SVM). The SVM input data are the amplitude of backscattered electric fields obtained from the accurate and efficient EM numerical simulation. How the spatial and frequency diversity affect the reconstruction is analyzed with respect to the characteristics of the scattered fields. Numerical experiments show that it is feasible to get an accurate reconstruction result with the backscattered multi-frequency data collected at just a few observation points which are specially selected based on scattering characteristics.