双尺度动态分形粗糙海面的电磁散射及多普勒谱研究

利用更为符合海面实际散射场计算的双尺度法分析并计算了一维动态分形粗糙海面的后向散射截面，同时与微扰法有关结果进行了比较.研究了动态分形海面后向散射信号的多普勒谱分形特征，分析了不同极化状态下后向散射截面和多普勒谱谱宽随入射角及分维的变化规律，最后详细讨论了多普勒谱中心频率与海面Bragg谐振频率间的关系. 关键词： 双尺度模型 分形海面 电磁散射 多普勒谱

Study on the electromagnetic scattering and Doppler spectra from two-scale time-varying fractal rough sea surface

In this paper, the two-scale model method, which is much applicable to the comp utation of the electromagnetic scattering field from the rough sea surface, is used to calculate the backscattering cross-section of the one-dimensional time-varying fractal rough sea surface, the related results are also compared with those calculated by small perturbation method. The fractal characteristic of the Doppler spectra of the backscattering signal from the sea surface is studied, th e dependances of the the backscattering cross-section and the width of Doppler s pectra on the incident angle and fractal dimension are also analyed. Finally, th e relationship between the central frequency of the Doppler spectra and the Brag g resonant frequency is discussed in detail.