共查询到18条相似文献,搜索用时 125 毫秒
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导体球涂覆各向异性铁氧体介质电磁散射的解析解 总被引:2,自引:2,他引:0
该文用球矢量波函数对各向异性铁氧体介质涂覆导体球的电磁散射解析解开展研究。各向异性铁氧体介质中电磁场的球矢量波函数解可表示成第一、二、三、四类球矢量波函数之和。根据球Bessel函数的性质,可以得出导体球涂覆各向异性铁氧体介质的球矢量波函数解析解。应用铁氧体与自由空间分界面上电磁场切向连续和在导体球面上切向电场等于零的边界条件以及球矢量波函数切向正交性质,可分别得出铁氧体介质中电磁场和散射场的展开系数。给出了平面波入射情况下的数值计算结果。该文的结果可应用于有关微波器件、天线以及目标特征的分析和计算。 相似文献
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在均匀旋电磁介质球矢量波函数的基础上,利用球Bessel函数的特性,给出了两层旋电磁介质球内的电磁场用波函数表示的表达式.在平面波入射情况下,应用电磁场在球边界上切向电场和磁场连续与远区辐射条件,导出了两层各向异性旋电磁介质中电磁场用矢量波函数表示的展开函数所满足的方程组,求出了两层旋电磁介质球的散射场用均匀各向同性波函数展开的展开系数,进而得出了两层旋电磁介质球对平面波的电磁散射特性.理论分析和数值计算的结果表明:当两层旋电磁介质球的媒质参数相同时,本文所得的结果可退化为单层各向异性旋电磁体解析解. 相似文献
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利用各向异性等离子体介质的电磁场满足各向异性等离子体球矢量波函数的条件,根据球Bessel函数的特点,分别给出两同心各向异性等离子体介质的球矢量波函数的解析表达式。在此基础上,应用电磁场在球边界上切向电场和磁场连续和远区辐射条件,导出在平面波入射情况下,两同心各向异性等离子体介质本征函数解的展开系数。理论分析和数值计算的结果表明:当两同心等离子体球媒质参数相同时,本文所得的结果可退化为单层各向异性等离子体解析解。同时数值计算还给出了本方法与矩量法-共扼梯度-傅立叶变换(MOM-CG-FFT)的比较结果,两者符合较好。 相似文献
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均匀无源各向异性等离子体介质中的电磁场是第一、第二类各向异性等离子体球矢量波函数的线性叠加,在阻抗球表面满足阻抗边界条件、等离子体与自由空间表面满足电磁场切向连续的边界条件,可得出各向异性等离子体涂覆阻抗球在平面波入射情况下,均匀等离子体介质中电磁场用各向异性等离子体球矢量波函数表示的系数满足的矩阵方程,进而得出散射场由球矢量波函数展开的展开系数和雷达散射截面.数值计算的结果表明:当阻抗球的半径趋于0时,其结果和均匀各向异性等离子体球对平面波的电磁散射结果相同.最后还给出了一些数值计算的结果. 相似文献
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三维各向异性介质目标电磁散射的MOM-CGM-FFT方法 总被引:12,自引:5,他引:7
给出了研究任意形状的三维各向异性介质目标的电磁散射问题一种混合计算方法。该方法以电场作为求知函数建立频域体积分-微分方程,使用脉冲基函数和点匹配函数的矩量法(MOM)将之转化为线性代数方程组。在求解过程中应用共轭梯度法9CGM)和快速富里叶变换(FFT)相结合的方法降低所需计算机内存和CPU时间。与各向同性和各向异性介质球的计算结果和解析结果及其它文献结果相比较,吻合较好。对材料参数为奇异矩阵的介质球的计算结果证明,该计算方法兼容性强,是一种求解三维电磁散射问题的有效途径。 相似文献
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本文给出了在空气与各向异性介质分界面上反射光、折射光与入射光振幅间的关系及其在测定各向异性介质主折射率中的一个应用。 相似文献
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You-Lin Geng Xin-Bao Wu Le-Wei Li Bo-Ran Guan 《Antennas and Propagation, IEEE Transactions on》2005,53(12):3982-3989
Electromagnetic scattering by an inhomogeneous plasma anisotropic sphere is formulated and obtained, where the inhomogeneous plasma anisotropic sphere is divided into (s-1) homogeneous anisotropic spherical layers. The electromagnetic fields in the inner spherical multilayers and outer free space of the inhomogeneous plasma anisotropic spherical structure can be expanded in terms of the spherical vector wave functions in plasma anisotropic medium and in isotropic medium, respectively. By applying the continuous boundary conditions of electromagnetic fields on the spherical interfaces of the (s-1)-layered homogeneous anisotropic plasma medium, the unknown expansion coefficients of fields in the multilayered plasma spherical structure are obtained, and then the electromagnetic field distributions are calculated. Numerical results for the very general inhomogeneous plasma dielectric material sphere are given and the data in a special case are obtained using the present method and the method of moments accelerated with the conjugate-gradient fast-Fourier-transform approach and compared to each other to verify the correctness and applicability of the present analysis. 相似文献
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Cheng-Wei Qiu Zouhdi S. Razek A. 《Antennas and Propagation, IEEE Transactions on》2007,55(12):3515-3523
We describe a novel and rigorous vector eigenfunction expansion of electric-type Green's dyadics for radially multi- layered uniaxial anisotropic media in terms of the modified spherical vector wave functions, which can take into account the effects of anisotropy ratio systematically. In each layer, the material constitutions e and epsiv macrmu macr are tensors and distribution of sources is arbitrary. Both the unbounded and scattering dyadic Green's functions (DGFs) for rotationally uniaxial anisotropic media are derived in spherical coordinates (r, thetas, phi). The coefficients of scattering DGFs, based on the coupling recursive algorithm satisfied by the coefficient matrix, are derived and expressed in a compact form. With these DGFs obtained, the electromagnetic fields in each layer are straightforward once the current source is known. A specific model is proposed for the scattering and absorption characteristics of multilayered uniaxial anisotropic spheres, and some novel performance regarding anisotropy effects is revealed. 相似文献
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VECTOR WAVE FUNCTION EXPANSION FOR SOLVING ELECTROMAGNETIC SCATTERING BY BURIED OBJECTS 总被引:1,自引:0,他引:1
An analysis of solving the electromagnetic scattering by buried objects using vectorwave function expansion is presented.For expanding the boundary conditions both on the planarair-earth interface and on the spherical surface,the conversion relations between the cylindricaland spherical vector wave functions are derived.Hence the vector wave function expansion isconveniently applied to solve this complex boundary-value problem.For the excitation of the in-cident plane wave and the dipole above the earth,the scatterlng patterns of the buried conductingand dielectric spheres are presented and discussed. 相似文献
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Chen Ru Shan K. F. Tsang Edward K. N. Yung 《Journal of Infrared, Millimeter and Terahertz Waves》2000,21(10):1703-1722
This paper presents an approximate but efficient field treatment of the new easy-to-fabricate ferrite sphere based H-plane waveguide circulator for potentially low-cost millimeter wave communication systems. A new three-dimension modeling strategy using a self-inconsistent mixed coordinates based mode matching technique is developed, i.e. the solutions of the Helmholz wave equations in the ferrite sphere and in the surrounding areas are deduced in the form of infinite summation of spherical, cylindrical and general Cartesian modes respectively. The point matching method is then used on the interface to numerically obtain the coefficients of different orders basis functions of the field. Therefore, the field distributions as well as the characteristics of the circulator are numerically calculated and the good agreement is observed between the numerical results and the measured data. 相似文献
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In this paper the spherical wave expansion technique is used to analyze the general properties of paraboloidal antenna feed systems. As a result, fundamental aperture efficiency and noise temperature limitations are established as quantitative functions of antenna wavelength size. A boundary-value solution is found for synthesis of ideal subreflector shapes in a Cassegrain-type feed system. The resulting surface is found to reduce the classical hyperboloid in the limit of zero wavelength. Applications of this synthesis technique to high performance feed systems and subreflector matching are discussed. Finally, an interesting quantitative cross-check between vector spherical wave and vector diffraction theories is obtained. 相似文献