共查询到20条相似文献,搜索用时 140 毫秒
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该文提出一种基于柱面扫描近场成像的RCS(Radar Cross Section)测量新方法:以理想的各向同性点散射中心模型为核心假设,通过详细的理论推导给出了一种具有通用性的基于柱面扫描近场成像的RCS 测量方法。该方法先得到目标的3 维雷达散射图像,再通过这些等效理想散射中心的散射场叠加获得远处散射场进而给出目标的远场RCS 值。该方法不仅能得到被测目标的3 维雷达散射图像,还能获得一定立体角域的目标远场RCS。相比只能得到2 维雷达散射图以及2 维平面角域RCS 结果的圆迹扫描测试相比,该文所提的柱面扫描测试能得到更多的目标散射信息,具有较强的实用性。仿真结果验证了新方法的可靠性。 相似文献
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求解目标地波散射特性的方法研究 总被引:6,自引:0,他引:6
本文把求解半空间散射问题的FDTD技术与地波传播理论相结合,研究任意复杂目标的地波散特性。入射地波设置在FDTD计算区域中的总场边界上并在散射场输出边界面上提取散射近场数据,然后利用等效及镜像原理,计算无地波衰减时的远区散射场,通过引入地波衰减因子,把该远区散射场转换为远区地波散射场,文中给出了方法验证例子以及一个较复杂目标的单站RCS计算结果。 相似文献
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本文给出推广的物理光学近似下理想导体目标的Fourier衍射定理,其形式与介质目标的相应关系式十分相似,利用这一关系式可以由测量直线上散射场分布重建二维理想导体目标Fourier域的空间谱值。通过简单例子讨论了这一关系式的适用性。 相似文献
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目标的雷达散射截面(RCS)与照射角度和照射频率都有关系,采用渐近波形估计(AWE)技术在角度域和频率域上预测任意形状的理想导体的单站RCS,通过Pade逼近求出给定角度域内任意角度及给定频带内任意频点的表面电流密度分布,进而计算出给定目标的散射场及雷达散射截面。对数值结果与矩量法逐点求解的结果进行了比较,两者吻合较好,而且提高了计算效率。 相似文献
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半空间环境中任意位置三维导体目标的电磁建模 总被引:2,自引:1,他引:1
采用基于混合位积分方程的数值方法对半空间环境中任意位置(包括界面上方、下方以及跨界面情形)的三维导体目标进行电磁建模,并通过以下两个途径来提高求解效率:一是优化阻抗矩阵的生成过程来避免格林函数的重复计算;二是在不同场源距离区域使用不同的索末菲积分计算方法(包括折合积分路径方法、最陡下降路径方法以及离散复镜像方法)来提高格林函数的单次计算效率.数值结果表明,该方法能方便地对半空间环境中任意位置目标电磁辐射与散射进行精确数值计算,同时具有较高的计算效率. 相似文献
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Image theory is developed for the canonical direct current problem involving a point current source in a conducting half-space bounded by a planar perfect anisotropic surface (PAS). The anisotropy of the surface is perfect in the sense that it has infinite conductivity in one direction and zero conductivity in the perpendicular direction. A PAS plane can be realized by a layer of perfectly conducting parallel wires isolated from one another. It is seen that the image of a current point source is a quadrupole transverse-magnetic current extending along a half-infinite line 相似文献
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The letter presents preliminary results from a recent experimental investigation to characterise the electromagnetic scattering from conducting objects submerged in a dissipative half-space. The variation of the magnetic field with respect to the depth of the scattering object is discussed. Correlations are also sought between the measured field components and the size of the scattering object. 相似文献
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The spectral theory of transients (STT) formulated in Parts I and II of this paper is here applied to the evaluation of the source-excited pulsed response for a representative class of two-dimensional examples: 1) a dielectric half-space with planar interface, 2) a dielectric half-space with curved interface, and 3) an edge-terminated curved perfectly conducting sheet. These configurations give rise to a variety, of propagation and diffraction phenomena such as those caused by lateral waves, by caustic-forming multiple reflected fields, by edge diffraction with formation of shadow boundaries, and by combinations of these. The results are established by direct utilization of the general formulas in Parts I and II, with emphasis on the spectral features associated with the various wave types. Sketches of the corresponding waveforms elucidate the behavior of the observed signal response. 相似文献
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Zhijun Liu Jiangqi He Yongjun Xie Sullivan A. Carin L. 《Antennas and Propagation, IEEE Transactions on》2002,50(12):1838-1849
The multilevel fast multipole algorithm (MLFMA) is considered for scattering from an electrically large conducting or dielectric target resting on the interface of a dielectric half-space. We focus on analysis of the half-space Green's function such that it is computed efficiently and accurately, while retaining a form that is applicable to an MLFMA analysis. Attention is also directed toward development of a simple preconditioner to accelerate convergence of the conjugate-gradient solver. The utility of the model is examined for several applications, including scattering from an electrically large vehicle, trees, and rough dielectric interfaces in the presence of a dielectric half-space background. 相似文献
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穿透叶簇的VHF/UHF超宽带(UWB)SAR具有相对带宽很宽,积累角大的特点,可同时获得距离、方位的高分辨能力,能用于探测叶簇隐蔽的军用车辆等人造目标而有着重要的军事应用价值。在VHF/UHF低频段,一般的人造目标可简单模化为目标主侧面与地表面之间形成的直二面角。本文详细推导了二面角人造目标光学区的散射场,建立了低频UWB雷达人造目标的光学区简化电磁模型,进而分析预测了二面角目标的散射特性。预测结果与外场试验分析得到的目标特性之间的一致性表明本文所建立的电磁模型是正确合理的。 相似文献
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The fast multipole method (FMM) was originally developed for perfect electric conductors (PECs) in free space, through exploitation of the spectral properties of the free-space Green's function. In the work reported here, the FMM is modified, for scattering from an arbitrary three-dimensional (3-D) PEC target above or buried in a lossy half space. The “near” terms in the FMM are handled via the original method-of-moments (MoM) analysis, wherein the half-space Green's function is evaluated efficiently and rigorously through application of the method of complex images. The “far” FMM interactions, which employ a clustering of expansion and testing functions, utilize an approximation to the Green's function dyadic via real image sources and far-field reflection dyadics. The half-space FMM algorithm is validated through comparison with results computed via a rigorous MoM analysis. Further, a detailed comparison is performed on the memory and computational requirements of the MoM and FMM algorithms for a target in the vicinity of a half-space interface 相似文献
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《Electromagnetic Compatibility, IEEE Transactions on》1995,37(1):105-109
Considers the problem of electromagnetic coupling between two half-space regions separated by multiple slot-perforated parallel conducting screens. The fields are considered to be excited by either a transverse electric (TE) or a transverse magnetic (TM) plane wave. A characteristic mode solution is used for the computation of the fields in each half-space. Special attention is given to the power transmitted from one half-space to the other through the slots and to its functional dependence on various parameters. Numerical examples are presented for illustration and comparison 相似文献
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Ling Li Jiangqi He Zhijun Liu Dong X. Carin L. 《Antennas and Propagation, IEEE Transactions on》2003,51(4):810-819
The multilevel fast multipole algorithm (MLFMA) is applied to the analysis of plane-wave scattering from multiple conducting and/or dielectric targets, of arbitrary shape, situated in the presence of a dielectric half-space. The multiple-target scattering problem is solved in an iterative fashion. In particular, the fields exciting each target are represented as the incident fields plus the scattered fields from all other targets. The scattered fields from each target are updated iteratively, until the induced currents on all targets have converged. The model is validated with an independent scattering algorithm, and results are presented for several example multitarget scattering scenarios. 相似文献