Characteristic Basis Function Method And Its Application To The Electromagnetic Scattering Problems

The problem of electromagnetic scattering is an important research domain in electromagnetics. It is very important and practical to analyze the electromagnetic scattering characteristics of multiple complicated objects quickly and efficiently. Characteristic basis function method (CBFM) is a novel approach for the efficient solution of electromagnetic scattering problems. It includes the mutual coupling effects directly by using a new type of high level basis functions, referred to herein as primary and secondary characteristic basis functions (CBFs). The characteristic basis functions used in this method are not restricted by the conventional domain discretization, the dimension of coefficient matrix in method of moments can be controlled by selecting the size of subdomain, and the matrix size can be reduced dramatically. Then these CBFs can be solved by the Galerkin method rather iterative method.The theory of the method of moments(MOM) is introduced firstly in this thesis, and some basic functions and testing functions are discussed, how to compute the radar cross sections of two-dimensional conducting objects and dielectric scatterers are also elaborated. CBFM based on Foldy-Lax multiple scattering equations is introduced then, which is a new approach for the electromagnetic scattering problems. This method is used to compute the radar cross sections for infinitely long multiple perfectly conducting elliptical cylinders and square cylinders and dielectric square cylinders. CBFM is also used to analyze electromagnetic scattering characteristics from two dimensional random dielectric scatterers and three dimensional random dielectric objects.The systematical analysis is given for the electromagnetic scattering characteristics of two-dimentional and three-dimentional multiple objects, by using CBFM for the first time in this thesis. The numerical results obtained by the presented method are in good agreement with that achieved by the traditional method of moments, the efficiency of computation is improved considerately.The investigation is very useful not only for quickly analyzing electromagnetic scattering of complicated random scatterers, but also in improving the teclinology of remote sensing, investigating land mine detection and new absorbing material and designing the wide-band radar, ultra wide-band radar.