Simulation framework for the evaluation of the radar channel transfer function in the near field of electrically large targets

A simulation framework to evaluate the radar channel transfer function in the near field of electrically large targets is presented in this article. The framework is based on the concepts known from physical optics adapted to the near-field conditions. The impact of the radar antenna characteristics on the scattering, which is non-negligible in the target near field, is incorporated by means of the antenna’s far-field radiation patterns. The inputs of the simulation framework are an STL-file-based model of the target and the gain and phase patterns of the antenna. The required sampling density of the target surface is examined in the context of convergence. The framework accounts for absorption effects due to dielectric or ohmic losses. Because the framework relies on direct evaluations without the need to solve equations, it exhibits a low computational effort, leading to fast computations. The applicability of the simulation framework is validated by measurements with different antennas at 24 and 61 GHz.