基于空间电荷波理论,导出了N间隙休斯结构耦合腔中注-波耦合系数和电子注电导计算公式,通过计算耦合腔中电子注的品质因数来分析电路的稳定性.研究表明,随着间隙数目N的增加,工作模式(2π模)稳定性对直流工作电压更加敏感,同时其他寄生模式的抑制会愈加困难.以三间隙休斯结构耦合腔为例,通过合理选择工作电压,2π模可以稳定工作,通常靠近2π模的π/2模可能更容易引发自激振荡. Based on the space charge wave theory, the calculation formulas of the injection-wave coupling coefficient and the electron injection conductance in the coupling cavity of N-gap Hughes structure are deduced. The stability of the circuit is analyzed by calculating the quality factor of the electron injection in the coupling cavity. The increase of the number of gaps N and the stability of the operating mode (2π mode) are more sensitive to the DC operating voltage, and the suppression of other parasitic modes becomes more and more difficult. Taking a three-gap Hughes-type coupling cavity as an example, by reasonably selecting the operating voltage, Stable operation, π / 2 mode, which is usually close to the 2π mode, may cause self-oscillation more easily.