共查询到17条相似文献,搜索用时 125 毫秒
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时域电场、磁场和混合场积分方程已被广泛用来分析散射体的时域散射响应.基于适当的空间积分方法和隐式的时间步进算(MOT)法在求解时域磁场和混合场积分方程时总是稳定的,然而在求解TDEFIE时则是不稳定的.在本文中,时域电场积分方程的非奇异性积分采用标准的高斯求积法来计算;而利用参数坐标变换和极坐标变换将其奇异性积分转换成为可以分区域精确快速计算的非奇异性积分.通过数值实验表明,利用该方法可以非常精确稳定地求解时域电场积分方程,即使是在时间迭代后期也不必采用任何求平均的过程;另外,该方法可以用于任意时间基函数并可以推广到高阶空间基函数的情形. 相似文献
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时域阻抗矩阵元素的计算需要分别计算场单元和源单元上的空时积分,由于时间基函数的分域性以及时间基函数(如三角型时间基函数)导数的不连续性,使得采用高斯积分方法计算源单元上空时积分的计算精度较差且误差随着时间步长的减小而增大.本文通过将源单元上空时积分转变成为1D时间卷积分和1D空间解析积分来精确计算时域阻抗矩阵元素,并在此基础上利用时间步进算法求解了时域电场、磁场和混合场积分方程.通过计算实例表明该方法在较大的时间步长取值范围内均能确保时域积分方程时间步进算法求解的精度和后时稳定性. 相似文献
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本文使用自适应交叉近似算法(Adaptive Across Approximation)加速时域积分方程的求解,从而达到降低内存
使用量和缩短计算时间的目的。众所周知,基于时间步进(Marching-On-in-Time)的时域积分方程的解会在时间轴后半
部分出现明显的震荡现象,造成解的不稳定。阶数步进(Marching-On-in-Degree)是解决这一问题的有效途径。因此,
本文首先采用MOD 方法求解时域积分方程,从而得到一个时间轴上稳定的解;其次,由于时域矩量法产生的大规模
稠密矩阵,其求解势必对内存以及硬件资源有着较高的要求。ACA 算法是一种纯数学加速方法,本文将它应用于时
域积分方程的求解过程中,有效地降低了资源需求。最后,通过算例验证了本文方法的有效性和可行性。 相似文献
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通过变量代换平滑三角形上推迟位(标量位函数和矢量位函数)并消除推迟矢量位旋度的奇异性,使得采用数值积分法就能够精确快速地计算任意正则时间基函数与推迟位函数及推迟矢量位旋度之间的时间卷积运算,可用于基于任意类型时间基函数的时域电场、时域磁场及其混合场积分方程时间步进(MOT )算法。与时间卷积运算的解析法对比分析表明,该时间卷积数值积分方法能够精确快速地计算基于任意类型时间基函数和不同时间步长条件下时域积分方程MOT算法的阻抗矩阵元素;而具体的计算实例也表明,阻抗矩阵的精确计算显著地提升了时域积分方程MOT算法的后时稳定性和求解精度。 相似文献
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We investigate the accuracy of the combined-field integral equation (CFIE) discretized with the Rao-Wilton-Glisson (RWG) basis functions for the solution of scattering and radiation problems involving three-dimensional conducting objects. Such a low-order discretization with the RWG functions renders the two components of CFIE, i.e., the electric-field integral equation (EFIE) and the magnetic-field integral equation (MFIE), incompatible, mainly because of the excessive discretization error of MFIE. Solutions obtained with CFIE are contaminated with the MFIE inaccuracy, and CFIE is also incompatible with EFIE and MFIE. We show that, in an iterative solution, the minimization of the residual error for CFIE involves a breakpoint, where a further reduction of the residual error does not improve the solution in terms of compatibility with EFIE, which provides a more accurate reference solution. This breakpoint corresponds to the last useful iteration, where the accuracy of CFIE is saturated and a further reduction of the residual error is practically unnecessary. 相似文献
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利用图形处理单元(GPU)加速混合场积分方程(CFIE)分析导体目标电磁散射问题。较电场积分方程(EFIE)和磁场积分方程(MFIE),CFIE消除了内谐振问题,并且具有更好的条件数。求解的数值方法为基于 RWG基函数的矩量法(MoM)。所有计算步骤均在 GPU上实现,包括:阻抗元素填充、电压向量填充、矩阵方程的共轭梯度(CG)求解、雷达散射截面(RCS)计算。在保证数值精确度的前提下获得了数十倍的速度提升。 相似文献
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A general method for deriving higher order impedance boundary conditions is described. It is based on solving an appropriate canonical problem exactly in the spectral domain. After approximating the spectral impedance terms as a ratio of polynomials in the transform variable, elementary properties of the Fourier transform are used to obtain the corresponding boundary condition in the spatial domain. The method is applicable to multilayer coatings with arbitrary constitutive relations. Higher-order boundary conditions which neglect the effects of curvature are derived for a dielectric coating using the method. The boundary condition equation and the magnetic field integral equation are solved simultaneously using the method of moments, yielding the bistatic and monostatic radar cross section for dielectric-coated superquadric cylinders. The method is also applicable to a combined field integral equation (CFIE) solution, which can be used to eliminate the internal resonance problem associated with either the electric field integral equation (EFIE) or magnetic field integral equation (MFIE) 相似文献
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Combined field integral equation formulation for inhomogeneous two and three-dimensional bodies: the junction problem 总被引:1,自引:0,他引:1
Putnam J.M. Medgyesi-Mitschang L.N. 《Antennas and Propagation, IEEE Transactions on》1991,39(5):667-672
A combined field integral equation (CFIE) formulation is presented for two- and three-dimensional bodies having discrete dielectric and conducting regions. A three-dimensional case is restricted to bodies of revolution (BORs). The two-dimensional case is analogous to the BOR case when the Fourier mode number is zero. The method of moments (MM) is used to solve the CFIE in terms of two integral operators. It is shown that the CFIE formulation yields accurate answers for scattering problems where the scatterer may be internally resonant. The CFIE results were validated using Mie series results and measured data. The junction problem associated with the CFIE-based formulation is explicated, and several geometries with multiple junctions are used to validate the general CFIE formulation. A number of configurations are tested where the penetrable region consisted of a free-space coating. Extensive numerical studies have shown that such limiting cases are sensitive indicators of the stability of MM solutions and allow direct comparison of different configurations 相似文献
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Combined-field integral equation 总被引:3,自引:0,他引:3
The combined-field integral equation (CFIE) is a linear combination of the H-field and the E-field integral equations. Previously, the weighting parameter of the E-field equation in the CFIE had been assumed constant along the generating curve of the body of revolution. However, it is shown that the weighting parameter can take a variable distribution along the generating curve or on a part of it only. In the latter case, a reduction in the computational time of 40-50% is achieved.<> 相似文献