Study And Application Of Boundary Integral Equation Method And Fast Algorithm For The Modeling Of The Complex Electromagnetic Problems

The objective of studying and developing modern computing electromagnetic theory and algorithm is to solve all kinds of engineering electromagnetic problems. In the areas of radar stealth and anti-stealth technology research, radar target identification, complex antenna system design and modern electric systems'EMC analysis, we often need to simulate the electromagnetic characteristics of some electric large objects which is composite of complex structure and complex medium. With these backgrounds, the object being investigated in this article is composite metallic and dielectric structure which is composed by piecewise homogeneous, linear and isotropic medium, the problem being investigated is the complex scattering and radiation problem, the intention being investigated is modeling and fast computing the electromagnetic characteristic of electric large complex structures with uniform method, the final objective is developing general fast electromagnetic computing software to solve the realize electromagnetic computing problems in engineering. For these proposes, we chose electromagnetic boundary integral equation (BIE) theory as the theoretical foundation, method of moments (MoM) as numerical process and the multilevel fast multipole algorithm (MLFMA) to accelerate the solving process and reduce memory requirement. The content of this thesis can be reduced to two parts, the first part expounds the boundary integral equation theory for composite metallic and dielectric structures and its resolving technique based on method of moments, the second part expounds the multilevel fast multipole algorithm and its stand-alone and parallel implements technique.In the first part of this thesis, the boundary integral equations for metallic structures, dielectric structures and composite metallic and dielectric structures are elaborated uniformly based on the surface equivalence principle and boundary conditions firstly. For an attempt to choose optimal BIEs for different structures, the applicability and excellence of different BIEs are compared. Then the solving procedures of these BIEs by the RWG functions based moment method are elaborated, and the method of modeling complex objects built of arbitrary line, surface and volume structures is developed. In order to solve realize antenna and circuit problems, methods of adding excitations and concentrated loadings with moment method are deceloped, and matrix pencil (MP) method is used to deembeded the S prameters of antennas and circuits from the computed current distribution. Some numerical results of practical complex antenna and scattering problems are presented to illustrate the veracity and effectiveness of the method.In the second part of this thesis, the basic principle of fast multipole method (FMM) is elaborated firstly. Then this method is used to accelerate the process of solving combined field integral equation (CFIE) of metallic problem and PMCHW integral equation of dielectric problem. The procedure of single level FMM and multilevel FMM are provided in detail. The...