共查询到17条相似文献,搜索用时 187 毫秒
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矩量法作为数值方法中积分方程方法的代表, 具有计算精度高、所用格林函数自动满足辐射条件、无须额外设置边界条件等优点. 但是在舰船目标与海面复合后向电磁散射仿真中, 传统矩量法需针对每个入射角反复求解矩阵方程组, 导致其在处理后向散射问题时计算量大, 耗时长, 仿真效率低下. 为解决上述问题, 本文提出了一种基于压缩感知技术的矩量法的改进算法. 该算法在求解复合后向散射问题时, 首先利用观测矩阵与传统矩量法中的电压矩阵相乘, 得到一组新的低维度的电压矩阵; 其次通过求解新电压矩阵下的矩阵方程组, 获得电流矩阵的观测值; 最后利用恢复算法(本文采用正交匹配追踪算法)重构出所需的原始入射源照射下的电流系数. 通过与传统矩量法的计算结果对比, 表明本文所提算法能够在保证计算精度的前提下, 明显减少计算时间, 提高计算效率. 相似文献
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基于矩量法、互易性定理及镜像理论,提出了一种新的混合方法用于研究水平分界面上方二维介质目标对垂直入射高斯波束的差值散射场.应用镜像理论,介质水平分界面可被原始目标相对于该分界面的镜像目标所替代,从而给出散射问题的等效模型.在等效模型中,应用矩量法求解了原始目标及镜像目标对高斯波束的散射场,同时结合互易性定理得到了原目标与其镜像目标之间的耦合散射场.数值计算结果与相关文献方法及MoM所得结果进行了比较,验证了该混合方法的有效性.
关键词:
互易性定理
电磁散射
高斯波束
二维目标 相似文献
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刻蚀波导粗糙面散射的矩量法数值分析 总被引:2,自引:2,他引:0
用矩量法对刻蚀波导粗糙面的散射特性做出了精确的数值分析基于MonteCarlo方法建立高斯粗糙面数学模型,证明矩量法在分析刻蚀波导散射问题时,是可以应用于不同起伏高度、不同入射角的一种精确而高效的数值方法对不同起伏高度的两种偏振态,分别在小角度入射和大角度入射两种情况的随机散射特性应用矩量法做出了分析并以基于二氧化硅波导的EDG器件为例,分析了由于波导壁粗糙对于器件频谱响应特性的影响. 相似文献
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海尖峰的存在会导致雷达虚警概率的上升和多目标环境中检测性能下降,因此研究海尖峰现象意义重大.海尖峰现象的一个重要特点是海面的水平极化散射强度接近甚至大于垂直极化散射强度,卷浪被认为是产生海尖峰的一个原因.首先建立了卷浪和Pierson-Moscowitz谱海面的共同模型,利用矩量法研究了卷浪模型的水平和垂直后向电磁散射特征,包括入射频率、入射角、风速和风向对电磁散射特征的影响.发现在小擦地角情况和较大风速下超级现象(水平散射强度大于垂直极化散射强度)比较明显,从而推论出在小擦地角入射下产生海尖峰现象的概率较大.同时对时变卷浪在小擦地角入射时的海杂波幅值分布特性和多普勒谱进行了分析. 相似文献
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为提高基于压缩感知技术的矩量法在三维电大目标双站电磁散射问题中的计算效率和稳定性,提出新的稀疏、测量和重构方法,构建一种新型压缩感知计算模型.不同于基于欠定方程的传统的压缩感知计算模型,新型计算模型首先采用按行均匀抽取阻抗矩阵的方法构造测量矩阵以获得稳定的计算结果;然后,基于Foldy-Lax方程生成多阶特征基函数并作为稀疏基对感应电流进行稀疏转换;再依据少数低阶特征基函数足以近似表征感应电流的先验条件,将恢复算法简化为最小二乘法;最后,将矩阵方程转换为一个超定系统并采用最小二乘法解出电流系数.与传统的计算模型相比,新型计算模型不仅可以获得更加稳定的精确解,还可以显著提高电大目标双站散射问题的求解效率和计算精度.数值仿真结果证明了新方法的可行性和高效性. 相似文献
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Efficient Solution to Electromagnetic Scattering Problems of Bodies of Revolution by Compressive Sensing
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《中国物理快报》2016,(1)
Under the theory structure of compressive sensing(CS),an underdetermined equation is deduced for describing the discrete solution of the electromagnetic integral equation of body of revolution(BOR),which will result in a small-scale impedance matrix.In the new linear equation system,the small-scale impedance matrix can be regarded as the measurement matrix in CS,while the excited vector is the measurement of unknown currents.Instead of solving dense full rank matrix equations by the iterative method,with suitable sparse representation,for unknown currents on the surface of BOR,the entire current can be accurately obtained by reconstructed algorithms in CS for small-scale undetermined equations.Numerical results show that the proposed method can greatly improve the computational efficiency and can decrease memory consumed. 相似文献
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Study of MPI based on parallel MOM on PC clusters for EM-beam scattering by 2-D PEC rough surfaces
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This paper firstly applies the finite impulse response filter (FIR)
theory combined with the fast Fourier transform (FFT) method to
generate two-dimensional Gaussian rough surface. Using the electric
field integral equation (EFIE), it introduces the method of moment
(MOM) with RWG vector basis function and Galerkin's method to
investigate the electromagnetic beam scattering by a two-dimensional
PEC Gaussian rough surface on personal computer (PC) clusters.
The details of the parallel conjugate gradient method (CGM) for
solving the matrix equation are also presented and the numerical
simulations are obtained through the message passing interface (MPI)
platform on the PC clusters. It finds significantly that the
parallel MOM supplies a novel technique for solving a two-dimensional
rough surface electromagnetic-scattering problem. The influences of
the root-mean-square height, the correlation length and the
polarization on the beam scattering characteristics by
two-dimensional PEC Gaussian rough surfaces are finally discussed. 相似文献
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提出了一种将压缩感知和特征基函数结合的方法来计算三维导体目标的雷达散射截面.利用压缩感知理论,将随机选择的矩量法阻抗矩阵作为测量矩阵,将激励电压视为测量值,然后再用恢复算法可实现二维或二维半目标感应电流的求解.对于三维导体目标,使用Rao-Wilton-Glisson基函数表示的感应电流在常用的离散余弦变换基、小波基等稀疏基上不稀疏.为此,本文将计算出的目标特征基函数作为稀疏基,用广义正交匹配追踪算法作为恢复算法来加速恢复过程,并应用到三维导体目标的雷达散射截面计算中.数值结果证明了本文方法的准确性与高效性. 相似文献
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利用MOM研究了不同土壤类型的一维有耗介质粗糙地面与其下方二维埋藏目标的复合电磁散射问题,在数值计算中,引入了锥形入射波以减少粗糙面模拟中由于人为截断所引起的计算误差.当给定入射波频率、土壤成分及土壤温度和土壤湿度后,可以根据相关模型计算出土壤的相对介电常数.数值结果以二维无限长导体圆柱为例,利用 Monte Carlo方法统计计算了双站复合散射截面随土壤类型、土壤湿度、入射波频率及均方根高度等的变化情况,并做了详细分析及讨论.该研究结果对于探地雷达在民用、军事、工业等多领域的应用具有一定的理论指导价值.
关键词:
粗糙地面
土壤类型
相对介电常数
四成分模型 相似文献
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针对分层媒质目标反演问题, 提出了一种基于等效电流源的目标重建方法. 该方法首先利用散射数据重建辐射电流源, 然后将等效电流源的求解转化为最优化问题来处理, 通过共轭梯度方法搜索得到全局最优解, 进而实现对目标的反演, 该方法充分挖掘了散射数据所包含的信息, 缩小了解的搜索空间维度, 具有求解效率高的优点. 深入研究了频率、 采样间隔、 采样长度、 噪声水平以及背景估计对反演结果的影响, 并对上述结果做了理论分析. 仿真结果表明, 该方法能够较好地实现分层媒质目标的反演, 可以应用于穿墙成像、地质勘探等领域.
关键词:
电磁散射
分层媒质
等效电流源 相似文献
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Compressive imaging based on multi-scale modulation and reconstruction in spatial frequency domain
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Imaging quality is a critical component of compressive imaging in real applications. In this study, we propose a compressive imaging method based on multi-scale modulation and reconstruction in the spatial frequency domain. Theoretical analysis and simulation show the relation between the measurement matrix resolution and compressive sensing(CS)imaging quality. The matrix design is improved to provide multi-scale modulations, followed by individual reconstruction of images of different spatial frequencies. Compared with traditional single-scale CS imaging, the multi-scale method provides high quality imaging in both high and low frequencies, and effectively decreases the overall reconstruction error.Experimental results confirm the feasibility of this technique, especially at low sampling rate. The method may thus be helpful in promoting the implementation of compressive imaging in real applications. 相似文献
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We calculate state-specified protonium-formation cross sections in low-energy antiproton-hydrogen-atom collisions by solving the Chew-Goldberger-type integral equation directly instead of integrating the traditional differential scattering equation. Separating the incident wave from the total wave function, we calculate only the scattered outgoing wave propagated by the Green function. The scattering boundary condition is hence automatically satisfied without the tedious procedure of adjusting the wave function at the asymptotic region. The formed protonium atoms tend to be distributed in higher angular momentum l and higher principle quantum number n states as the collision energy increases. The present method has the advantage over the traditional ones in the sense that the required memory size and the computational time are much smaller, and accordingly the problem can be solved with higher accuracy. 相似文献