A general method for finite difference time domain modeling of wave propagation in frequency-dispersive media
A general method for finite difference time domain modeling of wave propagation in frequency-dispersive media
复制标题
DOI：
10.7498/aps.57.6290
复制
发表时间：
2008-10
期刊：
影响因子：
--
通讯作者：
Wei Bing;Ge De-biao;Wang Fei
中科院分区：
文献类型：
--
作者：
Wei Bing;Ge De-biao;Wang Fei
由于介质的介电特性是频率相关的，因此在时域上电磁散射和传播的分析比较复杂。现有算法的一个缺点是需要为每个色散模型推导不同的公式。本文提出了位移算子时域有限差分（SO-FDTD）方法。首先，证明了三种一般色散介质模型的复介电常数。Debye模型、Lorentz模型和Drude模型可以用有理多项式函数在jω中描述。通过引入位移算子zt，导出了离散时域中D与E的本构关系。然后将移位算子法应用于一般色散介质情况。得到了可用于时域有限差分计算的D和E的递归表达式。最后，计算了色散球和被色散介质覆盖的PEC物体的散射。计算结果与文献和Mie级数解的结果吻合较好。这说明了所提出方案的通用性和可行性。
The analysis of electromagnetic scattering and propagation in dispersive media is complicated in time domain，because its dielectric property is frequency-dependent. A disadvantage of the prevailing algorithms is the need to deduce different formulations for each dispersion model. In this paper，the shift operator finite difference time domain (SO-FDTD) method is developed. First，we prove that the complex permittivity of three kinds of general dispersive media models，i.e. Debye model，the Lorentz model and the Drude model, may be described by rational polynomial functions in jω. By introducing a shift operator zt，the constitutive relation between D and E is derived in discretised time domain. The shift operator method is then applied to the general dispersive medium case. The recursive formulation for D and E available for FDTD computation is obtained. Finally，the scatterings by a dispersive sphere and a PEC object covered with dispersive media are computed. The computed results are in good agreement with the literature and the one obtained by Mies series solution. This illustrates the generality and the feasibility of the presented scheme.