一种提高FDTD近远场变换计算效率的方法

An advanced method of near to far field calculation with FDTD

时域有限差分(FDTD)法中的时域近远场变换法计算天线远场辐射特性的优点是通过一次计算可以得到全频域的结果,缺点是数据存储量大、计算速度慢。文献R.Pascaud、S.Wang和G.Carat介绍了一种基于二维空间数据压缩的时域近远场变换方法,此方法可以大大减少数据存储量从而减少近远场变换时间。基于减少数据量的考虑,本文提出一种基于时域抽样法的近远场变换算法以提高近远场变换计算效率。为验证新算法的有效性,分别用经典算法和时域抽样法对七单元八木天线远场辐射特进行计算,结果表明本算法可有效减少数据存储量,提高近远场变换效率。

The advantage of applying FDTD to calculate the far field using near-field to far-field transformation is that only one calculation is needed to obtain the fields in whole frequency band, but the disadvantage is huge mount of memory occupation and thus resulting in low speed of calculation. R.Pascaud, S.Wang and G.Carat introduced some methods by 2D spatial data compression to reduce the memory requirement and calculation time in time domain near-field to far-field transformation. The paper introduced a method of fast calculation the near-field to far-field transformation by simply reducing the samples in time-domain, and verified it by calculating the radiation fields of 7-element Yagi-Uda antenna. Results showed that the method can greatly improve the calculation efficiency with satisfied accuracy.