Simulation Analysis of S-Band Bistatic Returns From the Sea Surface at Low Grazing Angles

Sea clutter at low grazing angles has gained significant attention in studies of sea surface radar scattering. Previous research works on bistatic sea clutter at low grazing angles have primarily concentrated on analyzing clutter data obtained from the NetRad system. In this paper, we propose a new facet-based simulation method to study ocean surface returns of the S-band bistatic radar at low grazing angles. The proposed method can be used as a new tool to evaluate the effects of surface roughness and bistatic configuration on the scattering coefficients. It is a new implementation of the Physical Optics method, which we call the Facet Approximation Approach (FAA). Assuming a perfectly electrical conducting surface, we calculate the bistatic scattering coefficient and the scattering amplitude distribution using the Monte Carlo simulation method. The results indicate that the proposed method possesses a wider applicability range than Kirchhoff-Approximation and Small Perturbation Method, and remains effective at low grazing angles. At low grazing angles, both bistatic angle, incidence angle, and sea surface roughness have a significant impact on the scattering coefficient. Furthermore, the scattering amplitude distribution deviates from the Rayleigh distribution and exhibits a heavier tail.