A modified facet model is presented to solve the problem that the classical facet model in the synthetic aperture radar has large error of backscattered field from facets and results in blurring imaging in complex ocean surface. Firstly
an accurate model is built to calculate the permittivity of sea water with foams. Then
a concrete ocean surface is built based on the spectral model of Elfouhaily
and is divided into many little facets. The scattered field for each facet is calculated
and the result of electromagnetic scattering from ocean surface is obtained by superposing these scattered fields. A comparison with the measured data shows that when incidence angles are large
simulation results of the classical facet model appear an attenuation
while the modified facet model with foams reduces the attenuation about 10 dB and enhances the coincidence degree with the measured data. Experiment results by using the modified facet model to analyze the ocean surface electromagnetic scattering properties and Brewster effect show that the wind speeds influence the Brewster effect obviously. When the wind speeds at P-band increase from 4 m/s to 10 m/s
the Brewster effect is weakened about 85%.
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references
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