Characteristics of a signal backscattered from a rough water surface at small incidence angles

This paper presents the results of the experiment devoted to the study of the properties of the backscattered microwave signal at small incidence angles. Measurements have been carried out by the 3-sm Doppler radar mounted at the bridges across the Oka river in Nizhny Novgorod (the height of bridge is approximately 40 meters). During the measurements, two antennas are used: the knife-like antenna (δ_x²=1, 5° ; δ_y²= 24, 5°) and the parabolic one (δ_x²= 2, 4° ; δ_y²= 2, 4° ). Cycles of measurement are carried out separately for each antenna. Thus the developed model may be applied for the determination of the characteristics of the scattering surface using the parameters of the reflected signal. From the experimental measurements the theoretical calculations of power, shift and width of Doppler spectrum is obtained.