共查询到19条相似文献,搜索用时 265 毫秒
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基于四面体有限单元,采用高阶叠层矢量基函数分析腔体本征值问题,通过若干数值算例验证了在相同计算精度指标下,采用高阶基可以使用尺寸更大的网格,降低未知量个数,提高计算效率;并且通过加密网格,高阶基能够更快地收敛到真解。 相似文献
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针对传统矩量法在处理具有较多未知量的理想导体粗糙海面电磁散射问题时对计算机内存的需求过大, 耗时过长的缺陷, 文中引入了特征基函数法, 并根据Foldy-Lax多径散射方程构造特征基函数, 首先只考虑离散子域本身的自相互作用构造主要特征基函数, 然后考虑各离散子域间的互耦效应构造次要特征基函数, 最后由主要特征基函数和次要特征基函数的加权叠加构造特征基函数.通过与传统矩量法仿真结果的对比, 讨论了不同次要特征基函数的阶数或不同离散子域的个数对计算精度和计算效率的影响.仿真结果表明了本文所采用的算法能够在保证计算精度的前提下, 减少计算时间, 并能够通过离散子域尺寸的选取控制实际操作矩阵的维数. 相似文献
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Isernia T. Pascazio V. Pierri R. 《Geoscience and Remote Sensing, IEEE Transactions on》1997,35(4):910-923
A nonlinear estimation approach to solving the inverse scattering problem, and reconstructing the space-varying complex permittivity of unknown objects is considered. The bilinear operator equations governing the scattering are approximated into finite dimensional spaces on the basis of the finite degrees of freedom of data, and on the simple concept that one cannot expect to reconstruct an arbitrary function from a finite number of independent equations. As a consequence, a discrete model, well suited to numerical inversion, is developed. The particular bilinear nature of the equations, and a suitable choice of contrast and field unknowns allows the functional adopted in the estimation to be minimized in an accurate and numerically efficient manner. Numerical experiments show how the method is capable, when a proper number of searched unknowns is adopted, to manage the possible convergence to local minima (which is a typical question in nonlinear inverse problems), and validate the effectiveness of the proposed approach 相似文献
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Zhi-Guo Qian Tie Jun Cui Wei-Bing Lu Xiao-Xing Yin Wei Hong Weng Cho Chew 《Antennas and Propagation, IEEE Transactions on》2005,53(9):2969-2976
In this paper, an improved model is proposed to analyze the edge-connected line-fed patch antennas and printed circuits based on the method of moments (MoM), where the number of unknowns can be significantly reduced using simplified meshes. In the presented model, three types of basis functions are used to describe the currents on the antenna patch and circuit, the feedline and the feedline-patch junction. A new feedline-patch junction basis function is proposed based on the conventional wire-surface junction basis function. Numerical results are given to illustrate the accuracy and efficiency of the improved MoM model. 相似文献
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Hao Gang Wang Chi Hou Chan 《Antennas and Propagation, IEEE Transactions on》2007,55(5):1348-1358
We extend the multilevel Green's function interpolation method (MLGFIM) developed for quasi-electrostatic problems to full-wave simulations. The difficulty in applying the interpolation approach lies in the additional rapidly changing phase term associated with the full-wave Green's functions. To enhance the efficiency and accuracy of the full-wave Green's function interpolation, a scattered point set consisting of two staggered Tartan grids in conjunction with radial basis function interpolation is employed. To further reduce the computational complexity, the QR factorization technique is applied to compress the low rank Green's function matrices. For electromagnetic scattering from PEC spheres up to a diameter of eight wavelengths, the proposed method compares well with Mie's scattering in accuracy and shows the O(NlogN) efficiency. As the method is "kernel independent", its extension to structures in layered medium is straightforward. In the numerical simulations of finite microstrip patch arrays up to 11 by 11 elements, the proposed method demonstrates very favorable dependencies of CPU time and memory storage requirement versus the number of unknowns 相似文献
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Bruni S. Llombart N. Neto A. Gerini G. Maci S. 《Antennas and Propagation, IEEE Transactions on》2005,53(11):3556-3567
Problem matched basis functions are proposed for the method of moments analysis of printed slot coupled microstrips. The appropriate equivalent currents of the integral equation kernel are represented in terms of two sets of entire domain basis functions. These functions synthesize on one hand the resonant behavior of slots, microstrips or dipoles and on the other hand the field in proximity of the feeding source and of the discontinuities. In order to define these basis functions, canonical geometries are identified, whose Green's functions have been found in semi-analytical form. The accuracy and the effectiveness of the method in terms of convergence rate and number of unknowns is demonstrated by comparison with a standard fine meshing full-wave analysis. The method is extremely convenient for large arrays, where the subwavelength details should be treated together with large global dimensions. Since the proposed solution is independent of the dimensions of these details, it provides dramatic reduction of the number of unknowns and improvement of condition number. 相似文献
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三维散射与辐射问题通常采用电场积分方程(EFIE)结合矩量法(MoM)求解,而基函数是决定矩量法精度和效率的重要因素。本文针对采用三角形网格剖分会引起未知元过多而采用四边形网格剖分会因为网格质量变差而影响计算精度的问题,提出一种基于三角形与四边形混合网格的混合基函数,应用于散射体RCS和天线阻抗特性计算。结果表明,相比于三角形剖分,混合基函数能够在减少未知元个数的同时获得较高的精度;另外也解决了基于单纯四边形网格的基函数在网格质量较差的情况下不能准确模拟表面电荷的问题。 相似文献
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An acceleration technique to the fast multipole method (FMM) has been proposed to handle large-scale problems of periodic structures in free space with finite sizes based on the accurate sub-entire-domain basis functions. In the proposed algorithm, only nine (or 27) elements in the whole impedance matrix are required to be computed and stored for a two-dimensional (or three-dimensional) periodic structure, and the matrix-vector multiply can be performed efficiently using the combination of fast Fourier transform and FMM. The theoretical analysis and numerical results show that both the memory requirement and computational complexity are only of the order of O(N) with small constants, where N is the total number of unknowns 相似文献
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Parron J. Romeu J. Rius J.M. Mosig J.R. 《Antennas and Propagation, IEEE Transactions on》2003,51(8):1872-1876
The numerical analysis of highly iterated Sierpinski microstrip patch antennas by the method of moments (MoM) involves many tiny subdomain basis functions, resulting in a very large number of unknowns. The Sierpinski pre-fractal can be defined by an iterated function system (IFS). As a consequence, the geometry has a multilevel structure with many equal subdomains. This property, together with a multilevel matrix decomposition algorithm (MLMDA) implementation in which the MLMDA blocks are equal to the IFS generating shape, is used to reduce the computational cost of the frequency analysis of a Sierpinski based structure. 相似文献
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Wenming Yu Dagang Fang Chen Zhou 《Microwave and Wireless Components Letters, IEEE》2007,17(12):813-815
A marching-on-in-degree (MOD) based time-domain magnetic field integral equation method for bodies of revolution (BOR) is proposed and applied to obtain the induced currents on perfectly electric conducting BOR. Before this work, the time-domain integral equation method for BOR based on a marching-on-in-time procedure cannot really reduce the computational cost, since the number of unknowns cannot really be reduced. But it is the unknown reduction that serves as the key point of cost saving in BOR-problems. The method implemented in this letter can really utilize the symmetric property of BOR by applying two sets of entire domain basis functions. One is a set of scaled Laguerre polynomials inherited from common MOD method and used as temporal basis functions. The other is a Fourier series which comes from frequency domain method for solving BOR-problems. The validity, efficiency, and stability of the method are verified by several numerical examples. 相似文献