The Fast Physical Optics Method for Calculating the Scattered Field From the Rough Surface

In this paper, the fast physical optics (FPO) method for the scattering field of rough surface is proposed. The surface is discretized by quadratic patches. After transforming it into parameter coordinate system, the amplitude and function of physical optical integration are approximated by Lagrange interpolation polynomials. Finally, the closed-form formulas of FPO is obtained by using the complementary error function. Compared with the traditional method, FPO method can greatly reduce the number of patches when it is discrete, and the accuracy is within the acceptable error range. Numerical examples show the effectiveness of the proposed FPO method in accuracy.