Impact of the divergence factor on accurate RCS calculation using shooting and bouncing rays

The shooting and bouncing rays (SBR) method is a highly powerful technique for radar cross section (RCS) prediction of arbitrarily shaped targets. For the non-flat structures, the divergence factor (DF) plays an important role in accuracate RCS calculation. In practice, triangular surface mesh is widely used in computer aided design (CAD) representation for complex objects. Thus, the DF in SBR is often neglected and taken as unity. In this paper, the curvature matrices of the scattering surfaces are calculated using the surface reconstruction method. In this way, the DF can be conveniently computed by the condition of phase matching. Theoretical analysis and numerical simulations are conducted to show the numeric impact and significance of the DF correction in application of the SBR technique.