Research On Electromagnetic Modeling Technology For Scattering Center Imaging

The accurate modeling and efficient numerical algorithms for the electromagnetic(EM)radiation and scattering of the electrically-large structures are studied in this paper. It is discussed from four points. First, accurate electromagnetic modeling from complex structures; secondly, analyzing the fast algorithms, namely the adaptive cross approximation algorithm for wide-angle electromagnetic calculation; thirdly, analyzing the fast algorithms- adaptive interpolation technology for wide-band; finally, inverse synthetic aperture radar(ISAR) imaging and the extraction of scattering centers technology.Firstly, some numerical algorithms of the EM characteristics for electrically-large structures are briefly introduced. The integral equation method have been systematically studied, especially the numerical solution and critical techniques. According to the principle of equivalence, the surface integral equation(SIE), volume integral equation(VIE) and hybrid integral equation are established. The crux techniques-method of moment(MoM) for solving the integral equations and multilevel fast multipole algorithm(MLFMA) have been studied in detail.And, the adaptive cross approximation(ACA) algorithm are introduced, especially the basic mathematical theory and numerical implementation. Within the permissible error range, the efficient computation of wind-angle monostatic radar cross section(RCS) can be solved with adaptive cross approximation algorithm. Combining the advantage of MLFMA and ACA algorithm, ACA algorithm is realized. To improve the ACA algorithm of computing power, multilevel ACA algorithm is proposed.Then, wide-band electromagnetic scattering methods and their advantages and disadvantages are discussed. This paper proposes a new adaptive interpolation technology. The proposed method can precisely calculate the wideband electromagnetic scattering of target combined with MLFMA.Finally, detail work has been done for the problems of inverse synthetic aperture radar(ISAR) imaging and the extraction of scattering centers technology, such as the basic theory of ISAR, imaging algorithm and electromagnetic scattering mechanisms. To observe scattering centers intuitively, a adaptive CLEAN algorithm is proposed.This research work in the paper provides a effective way in accurate modeling and effective algorithms for EM radiation and scattering of the electrically-large structures. And it can be a solid foundation for the further research in this subject.