共查询到20条相似文献,搜索用时 31 毫秒
1.
针对带电导体附近急剧变化的位函数和场函数这一难于处理的边界条件,将小波函数的紧支撑特性和全域径向基函数(RBF)的高精度逼近能力相结合,提出电磁场边值问题求解的耦合方法并应用于接地金属槽/箱的数值计算中;将径向基函数无网格方法引入波导本征值的计算中,给出其求解本征问题的思路,建立相应的离散方程,分析矩形、圆形和脊形波导的本征值并与有限元方法进行比较.数值仿真实验表明,径向基函数及其耦合方法在分析电磁场边值和本征值问题时是有效的且具有实现简单、节点少和精度高的优势. 相似文献
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B. E. Fridman 《Technical Physics》2002,47(9):1112-1119
The diffusion of a pulsed electromagnetic field into massive conductors with an arbitrary smooth surface is considered for the case where the field penetration depth is small. By using the boundary layer method, an asymptotic solution for the electromagnetic field is constructed. First-and second-order corrections to the limiting solution, which corresponds to the field distribution at an indefinitely high conductivity of the conductors, are found. Time dependences of the first-and second-order approximations to the electric field on the surface of the conductor are determined. 相似文献
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The nonuniform current distribution in the transverse cross section of the coupled conductors of a microstripline made with
superconductor films leads to a substantial dependence of the losses in the line on the relative position of the coupled strips.
Analytical expressions are obtained in the static approximation for the current distribution in the coupled conductors for
even and odd modes, and the current distribution in the ground plane is found. The influence of the relative position of the
conductors on the impedance per unit length and on the damping of electromagnetic waves in a structure with coupled superconductor
lines are investigated for excitation of even and odd modes.
Pis’ma Zh. Tekh. Fiz. 67, 83–88 (February 1997) 相似文献
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K. L. Shukla 《Zeitschrift für Physik A Hadrons and Nuclei》1974,270(4):285-288
Penetration and reflection of an electromagnetic wave incident obliquely on a semi-infinite collisional plasma is studied. The linearized Boltzmann equation is used for the perturbed plasma. Using Fourier transform technique, specular boundary condition and simple collisional model the solution of coupled Maxwell-Boltzmann equations is presented. The field solutions consist of both longitudinal and transverse parts into the plasma region. The reflection coefficient is also obtained. 相似文献
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Z.W. Cui Y.P. Han J.J. Wang W.J. Zhao 《Journal of Quantitative Spectroscopy & Radiative Transfer》2012,113(6):480-488
A hybrid finite element-boundary integral method is applied to characterize the scattering of an arbitrarily incident-focused Gaussian beam by arbitrarily shaped inhomogeneous particles. Specifically, the Davis–Barton fifth-order approximation in combination with rotation Euler angles is used to represent the arbitrarily incident Gaussian beams. The finite element method is employed to formulate the fields in the interior region of the inhomogeneous particle, while the boundary integral equation is applied to represent the fields in the exterior region. The interior and exterior fields are coupled by means of the field continuity conditions. To reduce the computational burden, the frontal method and the multilevel fast multipole algorithm are adopted to solve the resultant matrix equation. Numerical results for differential scattering cross sections of several selected inhomogeneous particles are presented and can be served as further study on this subject. 相似文献
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Zhao S 《Optics letters》2011,36(16):3245-3247
This Letter introduces a novel finite-difference time-domain (FDTD) formulation for solving transverse electromagnetic systems in dispersive media. Based on the auxiliary differential equation approach, the Debye dispersion model is coupled with Maxwell's equations to derive a supplementary ordinary differential equation for describing the regularity changes in electromagnetic fields at the dispersive interface. The resulting time-dependent jump conditions are rigorously enforced in the FDTD discretization by means of the matched interface and boundary scheme. High-order convergences are numerically achieved for the first time in the literature in the FDTD simulations of dispersive inhomogeneous media. 相似文献
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Peijun Li 《Journal of computational physics》2010,229(2):481-497
Consider a time-harmonic electromagnetic plane wave incident on an inhomogeneity embedded in a two-layered medium. In this paper, a method of coupling of finite element and boundary integral equation methods is presented for the solutions of electromagnetic scattering in both transverse electric and magnetic polarization cases. The well-posedness of the continuous and discrete problems, as well as optimal error estimates for the coupled variational approximations, are obtained. Numerical results are included to illustrate the accuracy with the optimal convergence property of the proposed method and to show the wave features in a two-layered medium. 相似文献
9.
将矢量衍射数值算法—严格耦合波分析用于精确计算亚波长闪耀光栅的衍射效率,并分析其衍射特性。建立了闪耀光栅的电磁介质模型,并将楔形不规则结构简化为多层矩形光栅结构,通过电磁场的介质分布建立严格耦合波方程。根据边界条件求解出各层的电磁场分布,再通过增透矩阵方法将各层电磁场依次迭代,求解出了整个结构的衍射效率。计算分析显示,对闪耀角为11.3°、周期为500 nm的金属铝闪耀光栅可以得到高于90%的衍射效率和相应的闪耀级次。实验表明这种矢量衍射数值算法具有较高的准确性,可以推广应用于高致密刻线复杂光栅的衍射计算分析。 相似文献
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提出一种新时域交替隐式有限差分(ADI-FDTD)算法格式. 传统ADI-FDTD算法的 场量步进方程涉及周围若干网格的较多场量,导致两个区域的步进方程处理较困难:一个是 邻近完全匹配层(PML)和散射场交界区,另一个是邻近连接边界区. 特别是后者,考虑入射 波影响需对场量所在区域判断,根据不同情况对原有方程进行修正,一维和二维散射问题 相对简单,可三维问题修正式有数十种之多而几乎无法完成. 本方法基于分裂场形式的ADI- FDTD技术,使得散射场区和PML吸收层区的表达形式完全一致,从而忽略两者差别.另
关键词:
时域交替隐式有限差分算法
电磁散射 相似文献
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介绍了自主编制的3维全电磁粒子模拟大规模并行程序NEPTUNE的基本情况。该程序具备对多种典型高功率微波源器件的3维模拟能力,可以在数百乃至上千个CPU上稳定运行。该程序使用时域有限差分(FDTD)方法更新计算电磁场,采用Buneman-Boris算法更新粒子运动状态,运用质点网格法(PIC)处理粒子与电磁场的耦合关系,最后利用Boris方法求解泊松方程对电场散度进行修正,以确保计算精度。该程序初步具备复杂几何结构建模能力,可以对典型高功率微波器件中常见的一些复杂结构,如任意边界形状的轴对称几何体、正交投影面几何体,慢波结构、耦合孔洞、金属线和曲面薄膜等进行几何建模。该程序将理想导体边界、外加波边界、粒子发射与吸收边界及完全匹配层边界等物理边界应用于几何边界上,实现了数值计算的封闭求解。最后以算例的形式,介绍了使用NEPTUNE程序对磁绝缘线振荡器、相对论返波管、虚阴极振荡器及相对论速调管等典型高功率微波源器件进行的模拟计算情况,验证了模拟计算结果的可靠性,同时给出了并行效率的分布情况。 相似文献
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介绍了自主编制的3维全电磁粒子模拟大规模并行程序NEPTUNE的基本情况。该程序具备对多种典型高功率微波源器件的3维模拟能力,可以在数百乃至上千个CPU上稳定运行。该程序使用时域有限差分(FDTD)方法更新计算电磁场,采用Buneman-Boris算法更新粒子运动状态,运用质点网格法(PIC)处理粒子与电磁场的耦合关系,最后利用Boris方法求解泊松方程对电场散度进行修正,以确保计算精度。该程序初步具备复杂几何结构建模能力,可以对典型高功率微波器件中常见的一些复杂结构,如任意边界形状的轴对称几何体、正交投影面几何体,慢波结构、耦合孔洞、金属线和曲面薄膜等进行几何建模。该程序将理想导体边界、外加波边界、粒子发射与吸收边界及完全匹配层边界等物理边界应用于几何边界上,实现了数值计算的封闭求解。最后以算例的形式,介绍了使用NEPTUNE程序对磁绝缘线振荡器、相对论返波管、虚阴极振荡器及相对论速调管等典型高功率微波源器件进行的模拟计算情况,验证了模拟计算结果的可靠性,同时给出了并行效率的分布情况。 相似文献
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Using covariant quantization of the electromagnetic field, the Casimir force per unit area experienced by a long conducting cylindrical shell, under both Dirichlet and Neumann boundary conditions, is calculated. The renormalization procedure is based on the plasma cut-off frequency for real conductors. The real case of a gold (silver) cylindrical shell is considered and the corresponding electromagnetic Casimir pressure is computed. It is discussed that the Dirichlet and Neumann problems should be considered separately without adding their corresponding results. 相似文献
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本文对文献提出一些不同的见解,对联系边界条件有另外的提法,在处理方法上亦有不同。本文认为耦合槽可以分为浅槽和深槽两种形式,首先对槽口的电场作了近似估计,然后用格林张量函数求出矩形和圆形波导耦合时的电磁场,再用边界条件得出本征方程;对于本征方程,认为可以用两个电路的导纳相等来理解。本文亦对耦合波导管的传输常数和原有波导管传输常数加以讨论,最后再对某些应用上的问题加以简单的讨论。 相似文献
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Piezoelectric transducers coupled with a surrounding medium are analyzed in time domain using the coupled finite element and boundary element method. Three-dimensional solid elements are employed to model the piezoelectric transducer, while the surrounding medium is described by the boundary integral equation and the boundary of the medium is modeled by two-dimensional spatial elements. Verification studies were conducted to evaluate the accuracy and convergence of the present numerical algorithm and they show that the present numerical solutions agree well with the analytical ones. The influence of the surrounding medium on the acoustic field is studied. The interaction between the structure and surrounding medium affects the structure dynamic performances and acoustic pressure distributions significantly. However, in the present study we show that the radiation directivity is insignificantly influenced by the surrounding medium. 相似文献
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基于纤芯折射率增强的高双折射光子晶体光纤 总被引:2,自引:2,他引:0
通过增加光纤纤芯区域折射率实现了一种高双折射光子晶体光纤.采用全矢量有限元和平面波展开方法,系统地研究了这种高双折射光子晶体光纤在不同的高折射率区域参数(比如区域形状、折射率)情况下的光纤特性.模拟结果表明,光子晶体光纤的双折射可以在优化的参数条件下获得很大提高,光子晶体光纤的非线性系数(连同双折射)也可以同时得到提高. 相似文献