共查询到18条相似文献,搜索用时 296 毫秒
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本文利用迭代物理光学法(IPO)与数值方法相结合的混合方法计算二维开槽民大目标的电磁散射,首先根据等效原理将散射场进行分解,分别采用IPO法和矩量法(MoM)计算槽缝填充的电大目标和槽缝的散射,并在口径处应用广义网络原理处理耦合问题,数据结果表明本文方法是准确和高效的。 相似文献
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导电平面上槽与缝的散射 总被引:1,自引:0,他引:1
在雷达散射截面(RCS)和电磁脉冲(EMP)研究中,我们常常需要考虑目标上各个部分结合处存在的槽或缝的散射。在现代,随着RCS减缩技术的发展,这些槽和缝对目标双站散射行为的影响已经日益突出。对此,通过等效原理导出相应问题的全波公式,研究了具有不同形状和不同材料填充的槽或缝对目标散射图形的影响。 相似文献
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本文提出了一种分析电大开槽目标电磁散射的混合方法。根据等效原理,将原目标的散射场分为电大目标和槽缝散射场的叠加,前者用迭代物理光学法计算。对于后者,则先用时域有限差分法计算其导纳矩阵,然后在口径面上建立相应的广义网络模型,用网络分析的方法求得槽缝的等效磁流,最后由互易定理推得散射场的表达式,数值结果证明了本文方法的准确性和高效性。 相似文献
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与IPoverATM和IPoverSDH不同,由动态同步传送模式(DTM)提供的IPoverDTM(IPOD)解决方案,以其高效的协议、灵活的业务支持、强大的可扩展能力等显著优点,引起了ETSI等标准化组织的重视。文章从DTM原理出发,分析IPOD模型及其两种转发机制,探讨IPOD的应用实例和发展前景。 相似文献
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缝隙天线阵双站电磁散射的混合法 总被引:1,自引:1,他引:0
利用矩量法(MOM)和等效边缘电磁流方法(EECs)研究波导馈电的缝隙天线阵的双站散射问题。从理论和计算上分析,等效边缘电磁流方法可以计算有限尺寸的导体平板沿任意方向上的双站散射(包括边缘绕射场),而矩量法可以考虑波导缝隙天线阵的散射与耦合问题,使它们混合便可以解决有限尺寸缝隙在线阵的散射问题。实际计算表明,方法是切实可行的。 相似文献
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Tang Song Zhao Weijiang Liu Qizhong 《电子科学学刊(英文版)》2001,18(3):285-288
A hybrid technique to compute the surface-wave scattering of electrically large 2-D bodies with cracks by combining the current-based hybrid method and the finite element method is presented in this letter. Based on the equivalence theorem, the field scattered by a body with cracks can be divided into two parts: the scattering from the body without cracks and that from the cracks. Some numerical results have been obtained and the feasibility of the proposed methodis shown. 相似文献
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Jian-Ming Jin Ni S.S. Shung-Wu Lee 《Antennas and Propagation, IEEE Transactions on》1995,43(10):1130-1139
A robust hybrid technique is presented for an evaluation of electromagnetic scattering by large bodies with cracks and cavities on their surfaces. This technique employs the shooting-and-bouncing-ray (SBR) method to compute the scattering from the large bodies with the cracks and cavities filled with perfect conductors and the finite-element method (FEM) to characterize the cracks and cavities whose openings are covered with perfect conductors. A coupling scheme is then developed to combine these two methods in such a manner that (i) it includes all significant interactions and (ii) it permits the SBR and FEM to be computed separately. This results in an efficient and accurate computation of the scattering by large bodies with cracks and cavities. Several numerical results are presented, demonstrating the accuracy, efficiency, and capability of the technique 相似文献
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带有腔体或槽缝的电大尺寸目标电磁散射特性分析 总被引:9,自引:0,他引:9
本文提出了一种新的混合方法—FEM/PO-PTD法,应用于分析计算带有腔体或槽缝的电大尺寸复杂目标电磁散射问题.在该方法中,采用基于棱边的有限元法(edge-based FEM)为低频方法,物理光学法(PO)与物理绕射理论(PTD)为高频方法,通过耦合技术将两者结合在一起.为了验证该方法的准确性,本文首先将其应用于三维无穷接地开口腔体的电磁散射特性分析,计算结果与有关文献的数据一致性很好.在此基础上,给出了几种不同介质填充的三维开口腔体和带有槽缝的三维有限尺寸导体柱雷达散射截面的计算曲线,对分析有关工程问题有指导意义.理论分析与计算结果表明,本文提出的混合方法与其它计算同类问题的方法相比,能节省计算机存储单元、提高计算速度. 相似文献
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This paper presents an integral equation based scheme to analyze scattering from inhomogeneous bodies with anisotropic electromagnetic properties. Both the permittivity and permeability are assumed to be generalized tensors. Requisite integral equations are derived using volume equivalence theorem with the electric and magnetic flux densities being the unknown quantities. Matrix equations are derived by discretizing these unknowns using three dimensional Rao-Wilton-Glisson basis functions. Reduction of the integral equation to a corresponding matrix equation is considerably more involved due to the presence of anisotropy and the use of vector basis function; methods for evaluation of the integrals involved in the construction of this matrix is elucidated in detail. The method of moments technique is augmented with the fast multipole method and a compression scheme. The latter two enable large scale analysis. Finally, several numerical results are presented and compared against analytical solutions to validate the proposed scheme. An appendix provides analytical derivations for the formulae that are used to validate numerical method, and the necessary formulae that extends the approach presented herein to the analysis of scattering bianisotropic bodies. 相似文献
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The purpose of this work is to combine an extrapolation technique with the method of moments (MoM) to solve scattering problems involving large bodies. It has been shown in a previous work that the current induced on the smooth parts of large scatterers may be represented as a series of complex exponential functions with a few terms. Based on this concept, a hybrid set of basis functions is constructed using entire domain functions of complex exponential type on the smooth portion of the scatterer, complemented by subdomain basis functions near edges and discontinuities. An extrapolation procedure is developed in which the scattering problem is first solved for a portion of the scatterer using the conventional MoM. Next, a set of entire-domain basis functions, whose behaviour could be extrapolated with an increase in the size of the scatterer, is extracted from this original solution. The procedure outlined has the very desirable feature that the total number of basis functions remains unchanged even as the scatterer size is increased, allowing for large scatterers to be handled with a relatively small number of unknowns. The extrapolation technique is applied to scattering problems from bodies of revolution (BORs), and numerical results for an open cylinder and a barrel-shaped BOR are presented 相似文献
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Scattering from a large body with cracks and cavities by the fast and accurate finite-element boundary-integral method 总被引:5,自引:0,他引:5
Xin-Qing Sheng Yung E.K.-N. Chan C.H. Jin J.M. Chew W.C. 《Antennas and Propagation, IEEE Transactions on》2000,48(8):1153-1160
A large body with cracks and cavities is a typical structure widely existing in realistic targets. In this paper, a newly developed fast and accurate finite-element boundary-integral (FA-FE-BI) method is applied to compute scattering by this kind of scatterer. A thorough analysis on this FA-FE-BI numerical technique is presented, clearly demonstrating that this technique has computational complexity O(N log N) and memory requirement O(N) (N is the total number of surface unknowns). An inward-looking approach is employed as a preconditioner to speed up the rate of convergence of iterative solvers for this structure. Under these techniques, a powerful code is developed for this kind of scatterer whose accuracy, efficiency, and capability is well confirmed by various numerical results. 相似文献