Complex Electromagnetic Scattering Accurate Modeling Of High-level Fast Multipole Dipole Method

To realize efficient solution of electromagnetic (EM) scattering from complex target has very practical value for the design of radar system and identify of radar targets. The efficient solver for EM scattering from complex target includes two meaning. The first meaning is: It can realize accurate simulation and numerical computation of EM scattering from complex target under the available computer source condition. The numerical results have relative high accuracy and can agree with the measurement. The second meaning is: It can realize relatively fast analysis and computation based on the above condition. Hence, it is the important goal of scattering research that find a rigorous, efficient and accurate methods.The present paper applies fast multipole method (FMM) and multilevel fast multipole algorithm (MLFMA) based on the higher order moment of method (MOM) to solve scattering from complex target. The present methods can attain less unknowns,less computer memory requirement and better error convergence rate compared with low-order MOM, and maintain the virtue of high accuracy. The backscattering results of benchmark targets such as sphere, NASA almond, double ogive are given in this paper, they agree very well with the measurement. These numerical results prove the validity and high accuracy of the present methods. At first, the pivotal techniques of the basic method for solving the integral equation-MOM have been studied. They are: geometrical modeling of the object, choosing of basis functions and testing functions, , treatment of singularity of integral equations.Next,detailed discussion about two aspects of higher-order method: the higher-order geometrical modeling and higher-order basis functions are given. The paper researched some classes higher-order elements and basis functions. For electromagnetic scattering fromthree-dimensional conducting object, curvilinear triangular patch which be used to describe the surface of the scattering, combined with higher-order divergence conforming interpolatory vector basis functions is used to solute the problems. Scattering from some class three-dimensional conducting object is solved. Numerical results agree with other methods, the validity of the method and the program has been proved.Following, based on the above research foundation and aimed at resolving the scattering by the complex target with high efficient solution, extensive study of the FMM and MLFMA has been carried out. At first, the principles of FMM and MLFMA have been described. Subsequently, the combination of higher-order MOM with FMM has been implemented.