共查询到16条相似文献,搜索用时 140 毫秒
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基于等效原理和互易性定理研究了两个相邻目标的电磁散射问题,给出了这一复合电磁散射模型的二阶散射结果. 通常平面入射波的一阶散射结果容易求解,但由于耦合效应的复杂性,很难给出二阶散射结果的解析形式. 应用互易性定理给出了求解任意相邻导体/介质目标二阶电磁散射场的公式,并利用等效原理将求解散射场公式中的体积分简化为面积分的形式,从而降低了求解难度. 同时还推导了两个目标的二次散射场之间的关系. 最后应用给出的公式,求解了两相邻球形目标的复合散射场,对双站散射结果进行了讨论,同时与应用时域积分方程法求得的结果进行了比较.
关键词:
等效原理
互易性定理
电磁散射
相邻圆球 相似文献
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基于等效原理和互易性定理,研究了N个相互平行二维柱体对平面波/高斯波束的电磁散射特性,给出了求解N阶散射场公式.一阶散射可通过求解单个柱体的散射场得到,但对于高阶散射场而言,由于耦合散射的复杂性,很难给出精确的解析解.为了解决这一问题,借助等效原理和互易性定理给出了求解N阶散射场的面积分公式.只要给出柱体的i-1阶散射场及相关目标表面上的等效电流和(或)等效磁流,就可应用此公式求解i阶散射场.应用该近似方法计算了相互平行非均匀等离子体涂层导体圆柱的单/双站散射宽度,讨论了束腰半径、等离子体涂层厚度、电子密度、碰撞频率及雷达频率等对散射结果的影响. 相似文献
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基于矩量法、互易性定理及镜像理论,提出了一种新的混合方法用于研究水平分界面上方二维介质目标对垂直入射高斯波束的差值散射场.应用镜像理论,介质水平分界面可被原始目标相对于该分界面的镜像目标所替代,从而给出散射问题的等效模型.在等效模型中,应用矩量法求解了原始目标及镜像目标对高斯波束的散射场,同时结合互易性定理得到了原目标与其镜像目标之间的耦合散射场.数值计算结果与相关文献方法及MoM所得结果进行了比较,验证了该混合方法的有效性.
关键词:
互易性定理
电磁散射
高斯波束
二维目标 相似文献
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应用等效原理,通过引入口面上等效磁流将含腔导电目标电磁散射简化为腔内、外两个等效 问题. 腔内问题分段求解并应用级联法获得口面等效导纳矩阵;腔内外的耦合关系应用近似 边界元方法描述并由此获得口面等效磁流;最后,这一具有混合源的腔体内外一体化散射问 题则应用所提出的广义混合场积分方程方法建立电磁模型,并用多层快速多极子方法实现高 效数值求解. 实例计算结果与测试结果具有很好的一致性.
关键词:
含腔目标
电磁散射
混合场积分方程
数值分析 相似文献
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在电磁场积分方程方法框架下,应用等效原理求解了半空间背景下目标的电磁散射问题,可针对目标仅处于半空间界面单侧及目标跨越半空间界面处于半空间两侧的几何相对位置。与传统的半空间格林函数计算方法不同的是,这一方法使用的是各自介质的自由空间格林函数,因此可以回避索墨菲积分并且可以很方便与快速算法(如多层快速多级子)相结合,并对求解临近半空间界面的目标获得较好的收敛性。在等效原理方法中需要用有限的界面等效无限大半空间界面,因此采用了锥形入射波以降低开放边界引起的边缘效应。不同于一般目标的远场雷达散射截面表达,在该模型下,半空间电磁散射的远场描述需要用差场雷达散射截面。给出的算例能与现有文献以及仿真软件很好的吻合,并可作为实用工具分析半空间背景对目标远场响应的影响。 相似文献
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声显微镜模型及其反演 总被引:1,自引:0,他引:1
利用边界积分方程和机电互易原理得到声显微镜的模型,并对模型简化,得到了一个可以反演的形式,并利用频率和距离两参数的等效性,提出了一种反馈材料固液界面反射系数的方法。 相似文献
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Electromagnetic scattering from two parallel 2D targets arbitrarily located in a Gaussian beam 总被引:1,自引:0,他引:1 下载免费PDF全文
In this paper based on the equivalence principle and the reciprocity theorem, the
scattered field up to second-order by two parallel 2D targets arbitrarily located in
a Gaussian beam is considered. The first-order solution can easily be obtained by
calculating the scattered field from isolated targets when illuminated by a Gaussian
beam. However, because of the difficulty in formulating the couple scattering field,
it is almost impossible to find an analytical solution for the second-order
scattered field if the shapes of 2D targets are not canonical geometries. In order
to overcome this problem, in this paper, the second-order solution is derived by
using the technique based on the reciprocity theorem and the equivalence principle.
Meanwhile, the relation between the secondary scattered field from target #1 and
target {\#}2 is obtained. Specifically, the bi- and mono-static scattering of
Gaussian beam by two parallel adjacent inhomogeneous plasma-coated conducting
circular cylinders is calculated and the dependence of attenuation of the scattering
width on the thickness of the coated layer, electron number density, collision
frequency and radar frequency is discussed in detail. 相似文献
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Small particle light scattering can produce light with polarization characteristics different from those of the incident beam. An analytical solution to the scattering by a spheroid with inclusion for an on-axis polarized Gaussian beam incidence is provided within the generalized Lorenz-Mie theory framework. The shapes of the inclusion can be spherical, confocal spheroid, or non-confocal spheroid. The Muller scattering matrix elements are computed for plane wave incidence or Gaussian light beam incidence. The effect of the size and shape of the inclusion or the coating on the polarized Oaussian light scattering characteristics by a spheroidal water coating aerosol Darticle are commlted and a,nalvzed. 相似文献
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The scattered field of Gaussian beam scattering from arbitrarily shaped dielectric objects with rough surfaces is investigated for optical and infrared frequencies by using the plane wave spectrum method and the Kirchhoff approximation, and the formulae for the coherent and incoherent scattering cross sections are obtained theoretically based on geometrical optics and tangent plane approximations. The infrared laser scattering cross sections of a rough sphere are calculated at 1.06 μm, and the influence of the beam size is analysed numerically. It is shown that when the beam size is much larger than the size of the object, the results in this paper will be close to those of an incident plane wave. 相似文献
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粗糙表面激光散射特性的理论研究 总被引:8,自引:0,他引:8
用矢量微扰动方法分析激光束在粗糙表面上散射的分布特性。详细讨论高斯光束的角谱和适用于准直激光束散射问题的波前分割概念认为,当用入射总功率作归一化因子时,准直粗激光束散射可近似地作为平面波处理,而细激光束散射则与平面波存在很大的差异,利用所得结果讨论了一维粗糙表面的激光隐身作用及椭圆偏振光入射时镜反射方向和后向散射场的偏振态。最后介绍两种线偏振光在粗糙表面上散射分布的差异。实验验证了主要结论。 相似文献
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《Waves in Random and Complex Media》2013,23(3):277-286
Abstract The scattered field of Gaussian beam scattering from arbitrarily shaped dielectric objects with rough surfaces is investigated for optical and infrared frequencies by using the plane wave spectrum method and the Kirchhoff approximation, and the formulae for the coherent and incoherent scattering cross sections are obtained theoretically based on geometrical optics and tangent plane approximations. The infrared laser scattering cross sections of a rough sphere are calculated at 1.06 μm, and the influence of the beam size is analysed numerically. It is shown that when the beam size is much larger than the size of the object, the results in this paper will be close to those of an incident plane wave. 相似文献