丛状遮障的雷达散射特性分析

为研究丛状遮障的雷达散射行为,提出了一种兼顾周期性和遮障结构随机性的数值计算几何模型。该模型的最大特点是:一方面将遮障描述成周期结构以便于数值计算,另一方面则将遮障的随机结构特性赋予所计算的周期结构单元。赋予周期结构单元随机结构特性的方法是,在周期结构单元内放置大量的小叶片散射体,小叶片散射体的随机分布形成结构的随机性。这样的模型既克服了单纯周期结构无法反映遮障的结构随机性问题,也避免了单纯的随机结构难以计算的问题。利用所建立的模型进行了FDTD(finite difference time domain)计算,结果表明,随机结构遮障能够有效分散雷达回波,降低后向散射系数。

Radar diffraction features of flocculent screen

Ag eometry model w ith periodicity and randomicity w as put forw ard to analyze the microw ave dif fr act io n behavio r of the f locculent screen. T he peculiarity o f the model is that , on the one hand, the model tr eat s the f locculent screen as a periodic st ructur e to facilitate dig ital calculat io n; o n the other hand, the randomicity of the scr een is endowed to the periodic cell. T he perio dic cell of the model consisted of vast scat ters, and the randomicity of the st ructur e w as formed by the dist ribut ion of the scat ters in position and direct ion. Based on this mo del, the diff ract ion behav io r o f the flo cculent screen w as calculated by FDTD method. Result s indicate that the f locculent st ructure improves the camouf lage effect iveness o f the screen by dispersing the miacrow ave ener gy