基于FDTD的散射体宽角度宽频带RCS快速计算方法研究

将FDTD（Finite Difference Time Domain）法与双三次样条函数插值逼近、傅立叶变换结合,快速计算了三维散射体的宽角度、宽频带RCS（Radar Cross Section）。在双入射角度和全范围内各选定若干个插值节点,然后用FDTD法计算得到外推面上各节点的切向电磁场值,进而插值得到电磁场值随入射角度变化的双三次样条函数;之后用该样条函数计算出全入射角度范围内外推面上两个入射角范围内的切向电磁场值;最后通过近远场变换得到宽角度RCS。在计算过程中同时将激励源设置为脉冲源,通过对外推面上的电磁场值进行傅立叶变换,得到RCS频率响应。计算结果表明,只用少数插值节点就能够得到非常逼近FDTD法精确计算结果的散射体宽角度宽频带RCS响应,具有很高的计算效率。

Research on the Fast Calculation Method of Wide Angle and Wide Band RCS Pattern of Scatter Based on FDTD

Fast calculation of wide angle and wide band RCS （Radar Cross Section） pattern of scatter is obtained by the integration of FDTD, double cubic spline interpolation approximation and Fourier transform on this paper. Firstly, by using FDTD method to calculate the interpolative nodes in the range of incident angles and, the tangent electric and magnetic values on extrapolation boundary are obtained. Then the double cubic spline interpolation approximation functions related to incident angle are gained. Secondly, the tangent electric and magnetic values on extrapolation boundary in the whole scope of incident angle are calculated through the use of this approximating function. Relying on a near- to- far field transformation ,wide angle RCS pattern of scattering is gotten finally. After disposing the electric and magnetic values on extrapolation boundary by Fourier transform, and with pulse source, RCS frequency response is obtained. It is suggested in the numerical results that the wide angle and wide band RCS pattern of scatter, which is highly closed to the result through the use of FDTD, can be quickly achieved by using the method of this paper relying on only a few interpolation nodes, and the time cost is reduced greatly.