Some missions have been carried out to measure wave directional spectrum based on airborne real
aperture radar in a low incidence. For this study, the authors simulate the satellite-based real aperture
radar image spectrum to validate the radar performance of measuring the directional wave spectrum
based on the same principal as airborne one. In the processes of the simulation, the authors don't take
into account the rotation of antenna and the disturbing of the noise in order that the simulation can
exclude other factors to purely verify the measuring theory feasibility in essence. The authors use
Wen's spectrum as the input spectrum of the simulation, which is a kind of wind-generated wave
spectrum that can better describe the state of developing wave and the statuses of the Chinese sea fields.
Following that, the simulated sea surface, backscattered radar signal, modulation spectrum and the one
dimension wave spectrum (two dimension one can be obtained by synthesizing every directional one
dimension spectrum) are obtained, which is compared with the input spectrum. To have a
comprehensive realization to the performance of the radar, different cases including different
developing degree, wind speed and angle between dominant waves propagation direction and radar
look direction are considered. Presented results show that Satellite-based real aperture radar can mostly
measure the wave spectrum, but the capacity is limited on the cases of low wind speed, developing
waves and the big angles.