Numerical contour deformation method for calculating the scattered field from the electrically large convex scatterers

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.