An Improved SBR Method for Near-Field Scattering of Electrically Large Objects

This work proposes an improved shooting and bouncing ray (SBR) method for calculating the near-field scattering of electrically large objects. In near-field calculations, there is a divergence problem in the ray tube of the SBR method, which exacerbates the splitting of the ray tube. The traditional near-field SBR method suffers from accuracy loss, as the problem of ray tubes aperture divergence is only solved in first-order scattering calculations and is ignored in higher-order scattering calculations. This problem can be solved by dividing the ray tubes into denser ones, but this will reduce computational efficiency of the SBR method. This work proposes an adaptive tube subdivision method to control the ray tube aperture size and ensure ray tracing accuracy, which can effectively solve the problem of computational accuracy loss caused by tube divergence in near-field calculations, while taking into account the computational efficiency. Several examples are designed to verify the effectiveness of the method.