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基于粗糙面电磁散射双尺度模型推导给出了海面微波散射场多普勒谱频移和谱宽的理论公式,在该理论公式的推导过程中同时考虑了大尺度海浪的倾斜调制、遮蔽效应和曲率修正效应等因素的影响.文中将理论公式计算结果与精确数值结果进行了比较,并讨论了倾斜调制、遮蔽效应及曲率修正效应等因素对多普勒频移和谱宽的影响,发现倾斜调制使水平极化散射回波多普勒频移显著增大,从而导致水平极化回波多普勒频移比垂直极化回波多普勒频移大;在中等入射角度区域,遮蔽效应和曲率修正效应对多普勒谱并无显著影响,而在掠射条件下,遮蔽效应使得多普勒频移增大、谱宽变窄.本研究对深入理解动态海面散射场频谱特性具有一定参考意义.
Based on the two-scale model of electromagnetic scattering from rough surface, the theoretical formula of Doppler spectral shift and spectral width of the scattering field of the sea surface is given. In the derivation of the theoretical formula, the tilt modulation of the large-scale ocean wave, the shadowing effect and Curvature correction effect and other factors.In this paper, the calculation results of the theoretical formula are compared with the exact numerical results, and the effects of tilt modulation, shadowing effect and curvature correction effect on the Doppler shift and spectral width are discussed. The modulation causes the Doppler shift of the horizontal polarization scattering echo to increase significantly, resulting in a larger Doppler shift of the horizontal polarization echo than the Doppler shift of the vertical polarization echo. In the middle angle of incidence, the shadowing effect and the curvature correction Effect on Doppler spectrum has no significant effect, while in the grazing condition, the shadowing effect makes the Doppler shift increases, the spectrum width becomes narrower.This study has some reference significance for understanding the spectral characteristics of the dynamic sea surface scattering field.