缩比模型测量可以帮助缩短物体雷达散射截面(RCS)测量的时间，并减少其成本，而由于太赫兹波所处的波长范围的独特性，所以其在雷达散射截面缩比测量中有较多的应用。在对粗糙表面的散射截面计算中，可以将模型简化为带有突起的平板。单站散射（后向散射）是雷达系统中比较常用的一种测量方式，也有很多针对平面波入射情况下的计算，但是由于太赫兹源所产生的高斯光束的能量分布与平面波不同，得到的雷达散射截面的结果也与平面波不同，常常会导致测量结果和计算结果中有一定的误差。利用镜像法仿真计算了入射光为高斯光束时平板上的突起在2.52 THz频段处的雷达散射截面，详细比较了单站散射分别在二维和三维情况下，由于入射光为高斯光束对散射结果造成的影响。

Terahertz technology is widely used in the radar cross section (RCS), because the wavelength of terahertz can help downsize the model to a proper range and the measurement of scale model can help decrease the cost of time and the expenditure of the experiment. In the calculation of the RCS of a rough surface, sometimes, the question is deduced into the calculation of the boss on a flat plate and the monostatic radar is the one that mass of radar system adopted. However, a plane wave is usually assumed in most of the RCS estimation, while in real measurements, the energy of the incident beam obeys the Gaussian distribution. In the estimation, the influence of 2.52 THz collimated Gaussian beam on monostatic RCS is studied in details and the relatively error is analyzed.