混合尺寸目标电磁计算的时域伪谱/有限体积混合方法

针对单一算法对混合尺寸目标进行时域电磁分析的困难,提出一种时域伪谱(PSTD)同时域有限体积(FVTD)混合方法。FVTD可方便地分析复杂的几何结构和材料,但是难以计算电大尺寸的目标,PSTD则特别适合计算电大尺寸的规则结构,但在模拟复杂的几何结构尤其是带有曲边结构以及电大、电小共存结构时存在困难。混合方法克服了单独算法的缺点,融合各自的优势,提高了算法的求解能力和应用范围。为了减小两种算法连接边界带来的反射,采用了FVTD计算面均值的二次函数重构方法,给出了交叠网格和非交叠网格两种混合方案。数值试验表明,混合方法有较高的精度,具有时域分析混合尺寸目标电磁问题的能力。

A Hybrid PSTD/FVTD Method for Mixed-scale Electromagnetic Problems

A hybrid technique combining the Pseudo-Spectral Time-Domain method with the Finite-Volume Time-Domain method is presented to solve 3-D mixed-scale problems, which contain both electrically large and relatively homogeneous regions and electrically small fine details in computational electromagnetics. FVTD is suitable for electrically small problem but suffers from large numerical errors for electrically large-scale regions. The PSTD method, on the other hand, is accurate and efficient for regions with large and relatively homogeneous materials, but is low in efficiency for electrically small structures. The hybrid method overcomes disadvantages and unites advantages of either method mentioned and is potentially more useful. A least square based quadratic polynomial reconstruction method is developed for FVTD to reduce the reflection brought by the boundary of the algorithms, then an overlapping grids scheme and a no overlapping grids scheme are presented. Numerical examples demonstrate that the method proposed enjoys high level of precision and strong capability in region analysis.