时域有限差分法结合Pade逼近快速获取介质柱宽带RCS频率响应

Fast calculation of wide band RCS pattern of dielectric cylinders using the FDTD method and the Pade interpolation technique

由于时域信号的计算是在散射体近区内进行的,远区散射场的计算是通过近远场的变换而进行的。采用FDTD法计算散射体的宽频带RCS频率响应时,如果采用频域变换法,需要在很多频点上进行近远场变换计算。为此,本文引入Pade逼近,对FDTD法计算获得的、稀疏的RCS频率响应进行逼近,然后用获得的Pade有理逼近式计算宽频带RCS频率响应。计算结果表明Pade有理逼近式能很好地逼近FDTD法精确计算的曲线,同时计算速度可加快十多倍。

The mono-static RCS pattern of an arbitrarily shaped two-dimensional (2-D) dielectric cylinder is calculated by near-far field transformation, when selected method is the FDTD method. Because achieving the time domain signal of far field is very difficult, it is necessary to perform a lager of near-far field transformation when the wide band RCS is computed. In this article, the Pade interpolation technique is employed to obtain frequency domain results with satisfactory accuracy. By use of some RCS results, which are obtained using FDTD method, the rational function of RCS pattern can be achieved. Then the wide band RCS pattern can be calculated by use of the rational function. This reduces the computation time significantly compared with the conventional FDTD algorithm. The wide band RCS results computed by use of the Pade interpolation technique are compared with the conventional FDTD results. A good agreement is observed.