Abstract:The generation of far side-lobe echoes for offset parabolic antenna is analysed in this article,and the experiments have proved the existence of far side-lobe echoes.It is concluded that an offset feed parabolic antenna has the advantage in side-lobe suppression over central feed parabolic antenna.An offset antenna won’t generate far side lobe echoes when scanning in low elevation angles,but when the angles turn high,it will.In the application of Doppler radar,controlling the rotation speed of antenna is helpful in eliminating the effect of far side-lobes.