Abstract:Radar Cross Section(RCS) measurement under the terahertz band is one of the important research directions of terahertz radar. The system calibration technology determines the accuracy of the RCS measurement results. In this paper, RCS measurement system of terahertz wideband radar based on microwave frequency doubling source, the system has a central frequency at 440 GHz and its bandwidth is 25.6 GHz after the frequency doubled. Using a smooth surface metal sphere as the standard body, calibration of terahertz radar system by different times calibration technique, then the near field RCS measurement experiment of the fighter model and the jeep model of metal material are also carried out. Near field RCS measurements of two typical artificial targets have been obtained. The results are in good agreement with the theoretical trends, which proves the effectiveness of the time-sharing calibration technique in RCS measurement in terahertz radar systems.