Domain Integral Equation Method Using Time Domain Electromagnetic Scattering Of The Metal Dielectric Target

For a long time, frequency domain algorithm is the key computational method in computation electromagnetics field. With the increase of the engineering applications of imitate broadband signals and non-linear systems, a useful method which can imitate and analyze arbitrarily complicated metal-dielectric composite structure accuracy and stability is needed. Due to the Time Domain Integral Equation (TDIE) have large advantage for analyzing the electromagnetic scattering and radiation problem, using TDIE solve objects' scattering is a very important direction in computation electromagnetics field. There are two drawbacks of the classical MOT (marching-on-in-time)-based TDIE: the one is late time stability problem, the other is low computational efficiency problem. These drawbacks restrict the development of TDIE seriously. Many scholars in China and foreign countries have tried to improve these drawbacks, the late time stability problem is well solved these years, but the low computational efficiency problem is difficult to deal with effectively. Especially for the metal-dielectric composite objects which have large unknown quantity, the computational efficiency problem is urgently needed to solve. Instead of using classical accurate algorithm, this paper introduce an approach which using convolute integration to calculate the time domain impedance matrix and use it into the metal-nonmetal composite object, this approach improve the computational efficiency as well as good accuracy and late-time stability.At first, the TDIE theory bases of conducting objects and dielectric objects are introduced respective in this paper, deduce the computational process of Electric Field Integral Equation (EFIE), Magnetic Field Integral Equation (MFIE), Composite Field Integra] Equation (CFIE) in detail. The basic theory of Method of Moments (MOM) and far-scatter fields of metal-nonmetal composite object are also introduced.Then, discuss MOT(Marching-on-in-Time)-based TDIE in detail, Due to the importance of the accuracy of the time-domain impedance matrix elements, the techniques by which treating of the singular integrals arose from the TDIE-MOM solving process are analyzed in detail, using triangle patches discretizing arbitrarily 3-D metal-nonmetal composite objects surface and utilizing spatial RWG and temporal triangular bases, EFIE, MFIE and CFIE are solved by MOT algorithm. Several numerical results of three TDIE forms are compared.In the end, using convolute integration to calculate the impedance matrix of metal-nonmetal composite object, several classical numerical algorithms proved that using this approach improve the computational efficiency as well as the good accuracy and late-time stability.The research work presented in this dissertation provides an efficient approach to analyze the metal-nonmetal composite objects' time domain electromagnetic scattering phenomena, as well as a solid foundation for the further development in this subject.