根据空间电荷波小信号基础理论, 建立了多间隙耦合腔中单个间隙电子电导的计算模型与模式稳定性分析模型。以3间隙耦合腔为例, 推导出了各个间隙电子电导的计算公式。通过理论计算与仿真模拟, 研究了3间隙耦合腔中各个模式的电子电导特性, 并进行了间隙中注波互作用研究与模式稳定性分析。模型计算发现：各个间隙不同模式的电子电导不同, 第3间隙内电子电导受注电压及间隙距离影响最大, 对整个间隙内的注波互作用及电路稳定性的影响也最大。该模型还可以用于分布作用速调管注波互作用的计算模拟。

Based on the space-charge wave small signal theory, an electron conductance model of each gap in the multi-gap coupled cavity, a model for mode stability analysis, was presented. The formulas of each gap’s electron conductance in a three-gap coupled cavity were derived as an example. Through the theoretical and simulative method, the beam-loading of different cavity electric field modes was studied, and the beam-wave interaction and mode stability in the coupled cavity were analyzed. The calculation and analysis show that the electron conductances in different cavity gaps and gap field modes are clearly distinct. Compared with the electron conductances in the first and second gaps, the electron conductance in the third gap greatly depends on the beam voltage and gap distance, and therefore it has a principal effect on the beam-wave interaction in the cavity gap and the mode stability. In addition, the model can be used in the beam-wave interaction simulation of extended interaction klystron.