在由收发天线组成的探地雷达系统中，接收天线接收到的信号由直耦波、地面反射信号以及目标信号组成。地面反射和直耦波所组成的直达波远大于目标信号，从而使系统的信杂比降低。文中提出了一种通过在地面上加入分层平板介质对空气到土壤间阻抗进行宽带匹配的方法，该方法可以减小地面反射杂波，增加电磁波透入地下的信号。理论计算结果表明，通过选择合适的平板介电常数和厚度，在一定程度上将减小地面的直接反射回波，从而提高系统的动态范围和信杂比。

The system of ground penetrating radar consists of a transmitter and a receiving antenna.The total received signal is the sum of the direct coupled wave,the signal reflected from the ground and the signal scattered by the buried target.But the direct wave is usually much larger than the scattered signal,and the signal-to-clutter ratio of the ground penetrating radar(GPR) system is reduced.A method which can suppress the signal reflected from the ground through placing a layered dielectric slab is proposed in this paper.The clutter reflected from the ground is thus reduced,and the signal coupled into the soil is increased.The simulation results show that the reflected clutter can be reduced through selecting proper dielectric constant and thickness of the plate.So the method can improve the dynamic range and the signal-to-clutter ratio of the GPR system.

TN82

国家“863”资助项目（2001AA132020）