RCS Analysis of Open Cavity Structures Using Virtual Divergence Factor

This study proposes an improved shooting and bouncing rays (SBR) technique for accurate radar cross-section (RCS) analysis of curved cavity structures. Conventional flat-mesh-based SBR methods suffer from reflection direction errors because of discontinuous normal vectors and cannot track wavefront changes owing to the absence of curvature information. We employ surface fitting to estimate the local curvature, calculate continuous normal vectors, and apply a virtual divergence factor to compensate for energy convergence and divergence effects. Numerical experiments demonstrate that the proposed method achieves an NRMSE improvement of over 20 % compared to commercial software. The proposed technique can be effectively utilized for the RCS analysis of curved cavity structures.