共查询到20条相似文献,搜索用时 203 毫秒
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利用多层快速多极子方法(MLFMA)分析三维导体介质复合结构的电磁辐射与散射特性.根据等效原理,介质表面构造Poggio-Miller-Chang-Harrington-Wu(PMCHW)方程,导体表面建立电场积分方程(EFIE).分析了含介质目标MLFMA算法中远区组矩阵矢量相乘运算以及有耗媒质空间中格林函数的平面波展开.利用该方法研究了涂敷目标电磁散射特性以及天线罩对直线阵天线辐射特性的影响.MLFMA的应用降低了计算量和存储量,实现了对电大尺寸目标快速、准确的求解. 相似文献
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使用基于表面积分方程的矩量法来分析介质与理想导体混合体的电磁散射是计算电磁学的一大热点。对理想导体目标体表面建立电场积分方程,在介质目标体表面建立PMCHW方程组,与基于矩阵分块技术的自适应修正特征基函数法结合,对介质涂敷理想导体目标体的电磁散射进行分析,将其称之为EFIE-PMCHW-AMCBFM(E-P-AMCBFM)。并讨论不同参数如基函数阶数,矩阵块间重叠区域等对计算效率的影响,数值结果表明E-P-AMCBFM对于处理介质-理想导体混合体的电磁散射问题具有较高的精度和效率。 相似文献
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矩量法分析屏蔽导体内的多层介质多导体传输线 总被引:1,自引:0,他引:1
利用矩量法分析屏蔽导体内的多层介质多导体传输线。首先,建立该问题的算子方程;然后离散化算子方程,通过对导体和介质分界面的总电荷及介质和介质分界面自由电荷的自由空间二维格林函数分析,得出矩阵方程;最后得出屏蔽导体内多层介质中各导体的电容矩阵和电感矩阵。数值结果与现有类似结构分析结果相比较一致性较好。 相似文献
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用超宽带特征基函数法(UCBFM)分析扩展多导体目标的宽带散射特性。该方法保留了传统的特征基函数法(CBFM)可加速求解矩量法(MoM)中矩阵方程的优点,同时可通过将在最高频率点提取的超宽带特征基函数(UCBF),运用于其他频率点构建MoM减阶矩阵,实现快速频率扫描。相比于传统的CBFM,UCBFM因为不需要在每个频率点重复计算特征基函数(CBF),故可大大减少计算时间。该方法提供了一种快速分析目标宽带散射特性的解决途径。仿真计算了2×2导体球和3×1立方导体的扩展多导体宽带RCS频率响应,数值结果验证了该方法在此类问题求解中的有效性。 相似文献
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全电荷格林函数法是解决分层介质的多导体传榆线的参数提取的一个通用有效的方法,但是用矩量法处理时需将导体表面和介质分界面一起剖分,系数矩阵的阶数较大,计算效率降低。详细分析了多层介质多导体传榆线,并在矩量法处理时引入小波变换,使原稠密系数矩阵变换为稀疏矩阵。从而提高了求解速度。 相似文献
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特征基函数方法利用特征值分解提取目标散射特征,构造基于特征向量的基函数可以高效的缩减矩量法分析所需的未知量数目,有利于分析有限周期阵列电磁散射或辐射问题。然而,对于电大尺寸电磁阵列散射问题,直接求解由特征基函数组成的矩阵方程,仍然面临着计算量较大等问题,难以适用于单机计算。本文结合特征基函数和预修正傅里叶快速算法求解体面结合积分方程,分析了大型金属介质混合有限周期阵列的散射特性,该算法有效减少了计算量和计算时间,并且改善了迭代求解收敛性能。 相似文献
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The general problem of radiation/scattering from a dielectric coated semi-infinite conical structure excited by an arbitrary surface current distribution on the dielectric layer is formulated. Since the angular eigenfunction expansion is not suitable for this problem, the radial eigenfunction expansion is employed. The boundary value method is applied to obtain the fields in the form of infinite double series over the appropriate eigenfunctions in terms of spherical Hankel and associated Legendre functions. The conical dielectric shell may be lossy or lossless and the series solution generally involves complex eigenvalues which are calculated numerically. Using a small conducting sphere at the tip of the cone, the singularity of the Hankel functions at the origin is overcome, thus permitting the use of the orthogonality relations of Sommerfeld's complex-order wave functions to solve the problem and construct sets of infinite simultaneous linear equations which are presented in matrix form. 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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Sarkar T.K. Arvas R. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1989,77(5):788-795
An E-field integral equation for the computation of the radar cross section of finite composite conducting and lossy inhomogeneous dielectric bodies is presented. The equivalence principle is used to replace all conducting bodies by an equivalent surface electric current, and the dielectric is replaced by an equivalent volume polarization current. The respective boundary conditions on the dielectric and the conductor are utilized to solve for the electric current on the entire structure. Also the augmented conjugate gradient method is presented for the solution of extremely large systems of equations that arise in the present problem. Finally, typical results are presented to illustrate the potential of this method 相似文献
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The radiation properties of an axial slot antenna on a conducting elliptic cylinder with a homogeneous dielectric coating are investigated. In the dielectric coating and in the exterior free-space region the field is expanded in elliptic waves using the Mathieu functions. The Mathieu angular functions are employed as basis and testing functions to enforce the boundary conditions at the interface between the dielectric and the free-space regions. The equations of continuity at the boundary are solved by Galerkin's method. Numerical results are presented in graphical form for the transverse electric (TE) and transverse magnetic (TM) polarizations to illustrate the far-field radiation patterns, the gain versus coating thickness, and the aperture conductance versus coating thickness 相似文献
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Song J. Cai-Cheng Lu Weng Cho Chew 《Antennas and Propagation, IEEE Transactions on》1997,45(10):1488-1493
The fast multipole method (FMM) and multilevel fast multipole algorithm (MLFMA) are reviewed. The number of modes required, block-diagonal preconditioner, near singularity extraction, and the choice of initial guesses are discussed to apply the MLFMA to calculating electromagnetic scattering by large complex objects. Using these techniques, we can solve the problem of electromagnetic scattering by large complex three-dimensional (3-D) objects such as an aircraft (VFY218) on a small computer 相似文献
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Rao S.M. Cha C.-C. Cravey R.L. Wilkes D.L. 《Antennas and Propagation, IEEE Transactions on》1991,39(5):627-631
A simple and efficient numerical technique is presented to solve the electromagnetic scattering problem of coated conducting bodies of arbitrary shape. The surface equivalence principle is used to formulate the problem in terms of a set of coupled integral equations involving equivalent electric and magnetic surface currents which represent boundary fields. The conducting structures and the dielectric materials are modeled by planar triangular patches, and the method of moments is used to solve the integral equations. Numerical results for scattering cross sections are given for various structures and compared with other available data. These results are proved accurate by a number of representative examples 相似文献
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P. D. Kukharchik V. M. Serdyuk I. A. Titovitskii 《Journal of Communications Technology and Electronics》2007,52(7):725-732
The partial-domain method is applied to theoretically solve the problem of diffraction of a hybrid resonance mode by an inner ring slot and a cylindrical dielectric layer in a coaxial cavity with perfectly conducting walls of a finite thickness. The boundary equations for field amplitudes are solved with the use of Tikhonov’s regularization method, and a stable algorithm of calculation of the complex wave number (i.e., the resonance frequency and Q factor of free field oscillations) is developed. Conditions for the energy balance on the slot in the presence of a resonance are considered. Being independent of the field equations, these conditions complement them. 相似文献
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We present an iterative algorithm used for the computation of the scattering from arbitrary shaped bodies made of dielectric and conducting material. The harmonic problem is discretized by a hybrid boundary integral method/finite element method. To solve the discretized linear system, a modified version of a minimal residual algorithm has been developed for complex matrices. It takes into account the Lagrange multiplier constraint in a special way. This modified version also allows the linear system to be solved for many right-hand sides in an efficient manner 相似文献
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Sarkar T.K. Wonwoo Lee Rao S.M. 《Antennas and Propagation, IEEE Transactions on》2000,48(10):1625-1634
A time-domain surface integral equation approach based on the electric field formulation is utilized to calculate the transient scattering from both conducting and dielectric bodies consisting of arbitrarily shaped complex structures. The solution method is based on the method of moments (MoM) and involves the modeling of an arbitrarily shaped structure in conjunction with the triangular patch basis functions. An implicit method is described to solve the coupled integral equations derived utilizing the equivalence principle directly in the time domain. The usual late-time instabilities associated with the time-domain integral equations are avoided by using an implicit scheme. Detailed mathematical steps are included along with representative numerical results 相似文献