Bistatic scattering analysis for two-dimensional rough sea surfaces using an angular composite model

An angular composite model (ACM) is applied to analyse the bistatic scattering from two-dimensional sea surfaces. When the local scattered angle lies in the specular region, Kirchhoff approximation (KA) is used to evaluate the specular reflection, which predominates the total scattering in this region; the small perturbation method (SPM) is employed to deal with the diffuse reflection dominated by small roughness, as the local scattered angle is situated out of the specular region. This avoids dwelling on the tough question about how to choose the proper cut-off wave number like in the well-known two-scale model (TSM). Numerical illustrations are carried out for bistatic scattering coefficients versus wind speed, incident angle, incident frequency and polarization state, respectively. The comparison of numerical results of the ACM and other experimental and theoretical models in several configurations shows that the ACM is robust to give accurate numerical evaluations for bistatic scattering of rough sea surfaces.