电大凸目标电磁散射的数值路径变换算法研究

摘要

给出了基于Fock电流和增量长度绕射系数技术(Incremental Length Diffraction Coefficients, ILDC)得到的三维凸圆柱上的高频散射场的表达式,应用路径变换法和数值最速下降路径(Numerical Steepest Descent Path, NSDP)方法计算基于Fock电流的高振荡积分,得到散射场.数值算例显示,使用这一方法计算高频散射场,可以实现在不同频段的入射波下计算时间与频率无关.并给出一种基于测地线性质的爬行波寻迹算法,具有较高的精度和更高的计算效率,适用于任意光滑模型上爬行波的寻迹.%In this paper, we compute the high-frequency scattered field based on the Fock current and incremental length diffraction coefficients (ILDC) technique.However, a high oscillatory integration occurs when the high-frequency scattered field is calculated by the Fock current.So, we calculate the highly oscillatory physical optics integral by the contour deformation method and the numerical steepest descent path (NSDP) method.Numerical examples illustrate that the proposed NSDP method for calculating the high frequency scattered fields could achieve the frequency independent computational workload.Furthermore, we propose a creeping wave ray tracing algorithm based on geodesic curve.It achieves high accuracy and computational efficiency, and it can be applied to creeping wave ray tracing on models of arbitrary shapes.