随机耦合模型(RCM)是研究电磁脉冲干扰下波混沌系统中感应电压统计预测的新方法，其中波混沌腔体损耗因子的获取是这种方法使用的关键。从随机耦合模型理论出发，分析了损耗因子对腔体阻抗随频率变化特性的影响，探讨了不同损耗因子下归一化阻抗矩阵的统计特性，提出了使用腔体散射阻抗与辐射阻抗的比值作对照，以快速获取腔体损耗因子的新方法。

Random coupling model(RCM) for key parts of the complex electronic systems cavity to predict pulsed electromagnetic interfrence is a new method in studying high power microwave effects, while the damping of cavity is a key factor determining the effect of this statistical forecasting method. The effects that the cavity reactance varies with frequences is discussed in the first part of the paper. Then a new idea using the real part of cavity reactance vs radiation reactance to calculate the damping quickly is put forward. The method using matrix eigen values and comparison between radiation and scattering resistances is proposed to verify the feasibility of the new idea.