Abstract: Receiver and transmitter of monopulse radar are worked at the same frequency.This character of monopulse radar,receiving frequency is the same with emissive frequency,bings various echo interferences to radar.In planning of monoplulse radar,the reflected electromagnetic wave,which is come from the immediate vicinity of radar,has been considered.But the radar lacks a method to avoiding interference of the familiar cloud echo.In a cloudy or rainy day,the cloud echo would interfere with the radar's working.Thi...