共查询到18条相似文献,搜索用时 265 毫秒
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提出一种有限微带阵列电磁散射特性分析的有效方法。该法采用有限阵格林函数与矩量法相结合的方法,有效地解决了矩量法在大型阵列电磁特性分析中的计算效率问题;通过选取RWG基函数,使该法适用于任何单元形状的微带阵列。文中计算了矩形、十字形及圆形单元微带阵列的雷达截面,并与常规矩量法和参考文献的计算结果进行了比对,验证了该方法的有效性。 相似文献
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研究了小波变换在指数粗糙表面电磁散射中的应用.在用矩量法研究电磁散射问题时,基函数的选择是一个非常重要的步骤.不同的基函数对问题的求解规模影响很大.利用小波变换中二尺度方程关系,通过对大尺度基函数和小波基函数求解相应的矩阵方程,然后由小尺度基函数与大尺度基函数以及小波基函数的关系,求出对应于小尺度基函数的矩量法解.该方法的优点是减少了矩阵方程求解的规模. 相似文献
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周期特征模分析(PCMA)方法是一种有限周期阵列特征模分析数值算法。该方法使用特征向量在每个阵元上定义若干组全域基函数,然后基于全域基函数得到一个压缩广义特征值方程。利用该方程可实现该阵列的特征模分析。与传统方法相比,该方法未知数量显著减少,节省了存储成本和求解时间。然而,广义特征值方程中的矩阵元素计算涉及二重面积分,非常耗时。文章采用等效偶极矩法计算矩阵元素,避免了二重面积分运算,从而节省了计算时间。数值结果表明新方法的结果与PCMA法以及传统分析法结果吻合很好,验证了所提方法的精度。同时,该方法显著降低了求解时间。 相似文献
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针对曲面共形阵列结构电磁散射特性的高效、精确仿真分析需求,提出了一种并行综合函数矩量法处理方案.该方法是传统电磁经典数值算法——矩量法的一种改进形式,通过几何区域分解处理和综合基函数的方式极大降低了算法的内存消耗,使得单机分析电大尺寸问题和大规模阵列问题成为可能.更为重要的是,针对周期阵列结构,该方法具备综合函数复用特性和多区域并行处理特性,能够大大提高算法的综合处理效率.一个6×11的柱面共形贴片阵列被用于验证所提方法的性能,仿真结果表明,对于周期阵列结构,该方法的计算精度与多层快速多极子算法相当,虽然计算效率略低于多层快速多极子方法,但内存消耗比多层快速多极子方法低一个数量级. 相似文献
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Lucente E. Monorchio A. Mittra R. 《Antennas and Propagation, IEEE Transactions on》2008,56(4):999-1007
We describe a numerically efficient strategy for solving a linear system of equations arising in the Method of Moments for solving electromagnetic scattering problems. This novel approach, termed as the characteristic basis function method (CBFM), is based on utilizing characteristic basis functions (CBFs)-special functions defined on macro domains (blocks)-that include a relatively large number of conventional sub-domains discretized by using triangular or rectangular patches. Use of these basis functions leads to a significant reduction in the number of unknowns, and results in a substantial size reduction of the MoM matrix; this, in turn, enables us to handle the reduced matrix by using a direct solver, without the need to iterate. In addition, the paper shows that the CBFs can be generated by using a sparse representation of the impedance matrix-resulting in lower computational cost-and that, in contrast to the iterative techniques, multiple excitations can be handled with only a small overhead. Another important attribute of the CBFM is that it is readily parallelized. Numerical results that demonstrate the accuracy and time efficiency of the CBFM for several representative scattering problems are included in the paper. 相似文献
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Delgado C. Catedra M.F. Mittra R. 《Antennas and Propagation, IEEE Transactions on》2008,56(3):784-791
A novel implementation of the characteristic basis function method (CBFM) is given, in which the high-level basis functions, called characteristic basis functions (CBFs), are represented in terms of curved rooftops generated from nonuniform rational B-splines (NURBS) in the parametric (u,v) domain. The associated macro-testing functions are defined by using curved razor-blade functions corresponding to each rooftop. The underlying objective of the CBFM is the reduction of the number of unknowns that arise from the discretization process when applying the conventional method of moments (MoM). The result is, therefore, an approach which can handle many complex cases via direct solvers, without suffering from convergence problems as many of the iterative techniques are known to do when dealing with ill-conditioned matrices. As a result of the combination of the CBFM with the special class of low-level basis and testing functions directly located over NURBS surfaces, complex and realistic geometries can be efficiently analyzed to yield accurate results while reducing the CPU time as well as required memory resources. 相似文献
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《Antennas and Propagation, IEEE Transactions on》2006,54(9):2508-2514
A novel technique, based on a spectral domain integral equation method with analytically derived characteristic basis functions, is introduced in this paper. It enables us to treat scattering problems from electrically large faceted bodies in a numerically rigorous and computationally efficient manner, in terms of both time and memory. The analytically derived characteristic basis functions include certain desirable features of the asymptotic schemes and are defined on subdomains that can be electrically large, not being bound to the typical discretization size of the conventional method of moments. By properly weighting through a Galerkin procedure the resulting electric field integral equation, the problem is reduced to a matrix equation having dimensions that do not depend on the size of the scatterer but only on its shape. Electrically large problems can be handled in a computationally efficient manner by using the proposed method since the associated matrix size is relatively small; moreover, all the reduced matrix elements are calculated in the spectral domain without evaluating any convolution products. 相似文献
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《Electromagnetic Compatibility, IEEE Transactions on》2008,50(4):946-952
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Wei Shao Bing-Zhong Wang Zhong-Jun Yu 《Electromagnetic Compatibility, IEEE Transactions on》2006,48(1):10-18
A hybrid time-domain numerical method based on finite-difference technique and moment method is proposed. Starting from Maxwell's differential equations, our method uses Yee's finite difference scheme in the space domain, but does not utilize the customary explicit leap-frog time scheme. Instead, in the time domain, the fields are expanded in a series of basis functions and treated by a moment method procedure. By choosing appropriate basis functions and testing functions, the conventional finite-difference time-domain (FDTD) formulation and the order-marching unconditionally stable FDTD scheme can be derived from our method as two special cases. Finally, we use triangle basis functions and Galerkin's testing procedure to get an implicit formulation. To verify the accuracy and efficiency of the new formulation, we compare the results with the FDTD method. Our method improves computational efficiency notably, especially for multiscale problems with fine geometric structures, which is restricted by stability constrain in the FDTD method. 相似文献
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Higher order hierarchical discretization scheme for surface integral equations for layered media 总被引:2,自引:0,他引:2
Jorgensen E. Kim O.S. Meincke P. Breinbjerg O. 《Geoscience and Remote Sensing, IEEE Transactions on》2004,42(4):764-772
This paper presents an efficient technique for the analysis of electromagnetic scattering by arbitrarily shaped perfectly conducting objects in layered media. The technique is based on a higher order method of moments (MoM) solution of the electric field, magnetic field, or combined-field integral equation. This higher order MoM solution comprises higher order curved patches for the geometry modeling and higher order hierarchical basis functions for expansion of the electric surface current density. Due to the hierarchical property of the basis functions, the order of the expansion can be selected separately on each patch depending on the wavelength in the layer in which the patch is located and the size of the patch. In this way, a significant reduction of the number of unknowns is achieved and the same surface mesh can be reused in a wide frequency band. It is shown that even for fairly large problems, the higher order hierarchical MoM requires less memory than existing fast multipole method (FMM) or multilevel FMM implementations. 相似文献
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Matekovits L. Laza V.A. Vecchi G. 《Antennas and Propagation, IEEE Transactions on》2007,55(9):2509-2521
An innovative procedure is presented that allows the method of moments (MoM) analysis of large and complex antenna and scattering problems at a reduced memory and CPU cost, bounded within the resources provided by a standard (32 bit) personal computer. The method is based on the separation of the overall geometry into smaller portions, called blocks, and on the degrees of freedom of the field. The blocks need not be electrically unconnected. On each block, basis functions are generated with support on the entire block, that are subsequently used as basis functions for the analysis of the complete structure. Only a small number of these functions is required to obtain an accurate solution; therefore, the overall number of unknowns is drastically reduced with consequent impact on storage and solution time. These entire-domain basis functions are called synthetic functions; they are generated from the solution of the electromagnetic problem for the block in isolation, under excitation by suitably defined sources. The synthetic functions are obtained from the responses to all sources via a procedure based on the singular-value decomposition. Because of the strong reduction of the global number of unknowns, one can store the MoM matrix and afford a direct solution. The method is kernel-free, and can be implemented on existing MoM codes. 相似文献