Hermite插值结合FDTD法快速计算三维目标宽角度RCS

Fast Calculation of Wide Angle RCS Pattern of 3-D Object Based on Hermite Interpolation Technique and FDTD Method

Hermite插值结合时域有限差分(FDTD)法快速计算了三维目标的宽角度雷达散射截面(RCS)。一般用FDTD法计算散射体的宽角度RCS时,每改变一个入射角度,就需要重新用FDTD法计算一次。引入Hermite插值逼近方法可以节省计算时间。在整个入射角度范围内选定若干个入射角,对不同的入射角,分别用FDTD法计算得到外推面上各点的切向电磁场值及其对入射角的导数值,进而得到这些场值随入射角度变化的Hermite插值函数,然后用插值函数计算出全入射角度范围内外推面上各点的切向电磁场值,最后通过近远场变换得到宽角度RCS。计算结果表明在只有少数几个插值节点的情况下本文方法就能很好地逼近FDTD法的精确计算结果,节省了计算时间。

The wide angle radar cross section（RCS） pattern of 3D object can be quickly calculated by the Hermite interpolation approximation based finite-difference time-domain（FDTD） method.Generally,when calculating the wide angle RCS pattern of 3D object,FDTD calculation is needed to be performed once whenever the incident angle changes.Introducing the Hermite interpolation technique in FDTD method can save the calculation time.Firstly,several incident angles are chosen in whole range of angle,and FDTD method is employed with those angles one by one,and the tangent electric and magnetic values including differential values on extrapolation boundary are obtained.Then,the approximating functions related to incident angle are obtained.Secondly,the tangent electric and magnetic values on extrapolating boundary are calculated by approximating function in whole range of incident angle.Finally,wide angle RCS pattern of 3D object is calculated by a near-to-far field transformation. The numerical results are in good agreement with the results achieved by FDTD method at any incident angle,and the computational time is reduced.