Doppler spectra from bound waves in wind-wave tank

There exist bound gravity-capillary waves that move at the speed of dominate waves on the ocean surface, besides free gravity-capillary waves that satisfy the dispersion relation. In this paper, we propose a theoretic model to predict the Doppler shifts and bandwidths of bound and free waves. Additionally, we carry out the wind-wave tank experiments on microwave backscatter from ocean surface. Comparing with the measurements for different polarizations, and wind speeds, the formulae can be used to predict the Doppler bandwidths of bound waves and free waves.