Truncated size of the rough surface for calculating the backscattering RCS from combined objects

It is known that the time consuming step in the conventional hybrid Kirchhoff Approach-Method of Moment (KA-MoM) method is to calculate the interaction between objects and the rough surface. How to truncate the size of the rough surface is the key of solving this problem. In this paper, 3D problems are studied. According to the characteristics of the scattering at the incident plane and at the vertical plane of the incidence, two different approaches are proposed to reduce the size of the rough surface, and the adaptive selection method is used to find the length of the rough surface. The accuracy and efficiency of the proposed hybrid KA-MoM method are studied by numerical experiments.