Improvement Of Characteristic Basis Function Method And Its Application To Electromagnetic Scattering From Three-dimensional Dielectric Objects

The calculation of electromagnetic scattering is an important research domain in electromagnetics. It is very important and practical to analyze the electromagnetic scattering characteristics of multiple complex objects quickly and accurately. Characteristic basis function method (CBFM) is an important branch of the method of moments (MoM) and a novel approach for the fast solution of electromagnetic scattering problems, which is based on the conceptions of grouping and high-level basis function. In order to make full use of the CBFM, multilevel characteristic basis function method (ML-CBFM) based on Foldy-Lax multiple scattering conceptions is presented in this thesis. The size of the matrix and the computational accuracy are controlled by multilayer division of sub-blocks in the presented method.The theory of the MoM and the steps to analysis electromagnetic scattering characteristics are firstly introduced in the thesis. Then the volume integral equation of electromagnetic scattering from three-dimensional dielectric objects and how to use MoM to analyze electromagnetic scattering characteristics from three-dimensional dielectric objects are also introduced. The electromagnetic scattering characteristics of three-dimensional dielectric objects are analyzed by using CBFM based on Foldy-Lax multiple scattering conceptions. The numerical results are compared with that of the traditional MoM, validated the efficiency of this method. Then CBFM combined with the method of approximate calculation of mutual impedance is applied to symmetrical multiple dielectric objects. In order to reduce the storage requirements, only the self-impedance will be stored and the mutual impedance will be approximately calculated in real-time.What’s more,through in-depth analysis of the CBFM and trade off the computing time and calculation accuracy, ML-CBFM based on Foldy-Lax multiple scattering conceptions is presented. ML-CBFM is used to calculate the far field of three-dimensional dielectric objects. The numerical results show that the approach retains excellent accuracy and the computational efficiency is improved considerably in comparison with the traditional CBFM. To further validate the effectiveness of ML-CBFM, the presented method is used to analyze electromagnetic scattering characteristics from three-dimensional random dielectric objects, the spatial distribution of which is simulated by Monte-Carlo method, then numerical results are discussed.As a result, the CBFM based on Foldy-Lax multiple scattering conceptions and ML-CBFM are analyzed systematically, the investigation is very useful in further studying the electromagnetic scattering characteristics of electrically large objects.