基于箔条螺旋下降的运动模型，研究了箔条的转动和平动对箔条云回波信号造成的影响，用统计方法研究了 箔条云的全极化频谱特性.首先介绍了箔条螺旋下降的运动模型，给出了转动偶极子的极化散射矩阵，在此基础上 分析了箔条云散射矩阵元的自相关函数和互相关函数，给出了散射矩阵元的功率谱和交叉功率谱的表达式，然后 给出了均匀取向和水平取向箔条云回波频谱的数值结果.

Based on the spiral descending model of chaff， the effect of both rotation and translational motion of chaff on radar echo of chaff clouds was studied and the full-polarimetric spectral characteristics of radar echoes from chaff clouds were investigated by using statistical method. Firstly， spiral descending model of chaff was described， and the Sinclair matrix of a dipole with rotation was given. Based on the above analysis， auto correlation and cross-correlation functions of the Sinclair Matrix elements were investigated and further power spectrum and cross-power spectrum were derived. At last， some numerical results of radar echo spectra for randomly oriented and horizontally oriented chaff clouds were presented.