共查询到18条相似文献,搜索用时 93 毫秒
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提出了一种全新的FDTD吸收边界条件——线性预测吸收边界条件(Linear Prediction Absorbing Boundary Condition——LPABC)。通过对吸收边界上的入射场进行深入的分析研究,发现在某些条件下吸收边界上的场值与入射方向上其相邻区域的场值是线性相关的,从而提出了一种利用入射方向相邻区域的场值对吸收边界上的场值进行线性预测的吸收边界条件。采用这种吸收边界条件,计算域内的场为行波场,在边界处是无反射的。此外,这种吸收边界条件不需要设置额外的吸收层,也不需要存储前一时刻的场值。最后进行了FDTD实际计算,计算结果表明LPABC吸收边界条件是有效的。 相似文献
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提出了两种适用于任意正交曲线坐标系下时域电磁散射问题计算的吸收边界条件,这两种吸收边界条件均具有二阶精度。作为比较,也给出了与其他几种常用边界条件的比较结果。 相似文献
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本文对高阶Higdon吸收边界条件的直接实现方法进行了研究,给出了高阶吸收边界条件差分形式系数的具体计算方法和有关参量的选择方法,并对采用这些系数的Higdon吸收边界条件进行了时域有限差分(FDTD)数值检验与Mur边界条件进行了比较,结果表明,适当选择有关参量,高阶Higdon吸收边界条件在垂直入射和非垂直入射时的计算精度都明显高于Mur边界条件。 相似文献
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将理想匹配层(PML)吸收边界条件和模式匹配法用于多段平面光波导结构分析,给出了一种改进的平面光波导结构的PML吸收边界条件,并对光波导的光场分布进行数值模拟,所得结果表明了PML吸收边界条件应用于多段平面光波导结构分析的有效性。该方法也可用于分析复杂结构的平面光波导。 相似文献
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本文分析了Mur吸收边界条件产生误差的原因,讨论了用散射中心法校正Mur吸收边界条件的问题,以二维情况下线源的辐射及方柱形导体的散射问题为例进行编程计算,且与未校正的同阶和高阶近亿的Mur吸收边界条件作了比较,证明该方法是有效的,最后提出用坡印亭矢量的来校正Mur吸收边界条件的思想。 相似文献
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理想匹配层(PML)是近年来迅速发展起来的一种非常有效的吸收边界.本文基于模式匹配法将PML吸收边界条件用于平面光波导结构计算中,从理论上分析了PML吸收边界条件的有效性,并在PML边界条件下模拟计算了一个三段平面光波导结构的模场分布. 相似文献
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几种新的吸收边界条件在电磁散射中的应用 总被引:7,自引:2,他引:5
在应用FDTD求解电磁散射问题时,需要引入了吸收边界条件来截断计算空间。将Z变换域上导出的几种新的吸收边界条件应用于三维电磁散射问题的分析。通过数值计算验证了这几种吸收条件的有效性并与MOM法等进行了比较。 相似文献
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Jiayuan Fang 《Microwave Theory and Techniques》1994,42(8):1506-1513
A general expression of an absorbing boundary condition is presented in this paper to model wave propagation in passive microwave integrated-circuits by the finite-difference time-domain method. Unlike previously developed absorbing boundary conditions which can only absorb propagating waves, this boundary condition can also absorb evanescent waves effectively. The microstrip line is used as an example to demonstrate how to impose this absorbing boundary condition on different outer boundaries of a computation-domain. It is also demonstrated that the numerical stability of this absorbing boundary condition, when it is applied in its high order form, can be maintained by properly selecting its parameters 相似文献
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The authors propose a technique, which they call superabsorption, for improving absorbing boundary conditions in finite-difference time-domain methods. This method can be applied to every known absorbing boundary condition and greatly reduces the numerical error caused by the boundary reflection. The principle and analysis of the superabsorption method are presented. Numerical tests indicating the improvements obtained on many absorbing boundary conditions are reported 相似文献
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Absorbing Boundary Conditions for the Finite-Difference Approximation of the Time-Domain Electromagnetic-Field Equations 总被引:23,自引:0,他引:23
When time-domain electromagnetic-field equations are solved using finite-difference techniques in unbounded space, there must be a method limiting the domain in which the field is computed. This is achieved by truncating the mesh and using absorbing boundary conditions at its artificial boundaries to simulate the unbounded surroundings. This paper presents highly absorbing boundary conditions for electromagnetic-field equations that can be used for both two-and three-dimensional configurations. Numerical results are given that clearly exhibit the accuracy and limits of applicability of highly absorbing boundary conditions. A simplified, but equally accurate, absorbing condition is derived for two- dimensional time-domain electromagnetic-field problems. 相似文献
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Tirkas P.A. Balanis C.A. Renaut R.A. 《Antennas and Propagation, IEEE Transactions on》1992,40(10):1215-1222
Higher-order absorbing boundary conditions are introduced and implemented in a finite-difference time-domain (FDTD) computer code. Reflections caused by the absorbing boundary conditions are examined. For the case of a point source radiating in a finite computational domain, it is shown that the error decreases as the order of approximation of the absorbing boundary condition increases. Fifth-order approximation reduces the normalized reflections to less than 0.2%, whereas the widely used second-order approximation produces about 3% reflections. A method for easy implementation of any order approximation is also presented 相似文献
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柱坐标系下FDTD算法的吸收边界条件 总被引:5,自引:2,他引:5
本文借助二阶准波方程式研究了柱坐标系下FDTD算法的一种吸收边界条件.根据这一边界条件,编制了相应的计算程序检验其吸收特性,并与均匀柱面波传播的简单吸收条件作了比较.计算结果表明,该吸收边界条件具有较好的吸收性能. 相似文献
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完全匹配层(PML)吸收边界条件的理论分析 总被引:4,自引:0,他引:4
本文以屏蔽微带线为例,应用谱域方法推导了时域差分(FDTD)法中所用的完全匹配层(PML)吸收边界条件的公式,并且严格证明了有关参数的选择原则.计算表明,在屏蔽微带线中,这种吸收边界条件的反射系数可以小于-80dB.本文所给出的推导方法对于平面分层介质结构是普遍适用的,因为谱域中的每一个波谱实际上都代表一个平面波.文中所给出的推导揭示了这种吸收边界条件的机理,它对于正确使用以及进一步改进这种吸收边界条件都是有意义的. 相似文献