Effect of antenna footprint on the statistics of radar backscattering from random surfaces

The effect of antenna beamwidth on the statistics of radar backscattering from random surfaces is studied. One-dimensional perfectly conducting random surfaces having Gaussian height distributions and correlation functions are considered. Then, the method of moments is used to solve for the scattered field from the segments of the random surface when a Gaussian beam with variable footprints is used as the incident wave. The vv- and hh-polarized backscattering coefficients are computed using a large number of independent surface segments to get accurate statistics at various incidence angles. It was found that the antenna footprint should be at least twice as long as the correlation length so that the backscattering coefficients become independent of footprint size