Abstract: Electromagnetic scattering from the rough surface using the small slope approximation is investigated, which gives a systematic expansion of the scattering cross section that can be interpreted as a series in the generalized surface slope, with the bistatic scattering cross sections for the Gaussian conducting rough surface under the first, second and third-order small slope approximation obtained. The results by the small slope approximation are also compared with those of the Kirchhoff approximation with the shadowing effect considered and the experimnetal data, which shows that the small slope approximation is more accurate for the whole region of the incident angle and the numerical results also show good agreement with the experimental data for the large scattering angle.

Key words: small slope approximation, Kirchhoff approximation, shadowing effect, electromagnetic scattering