休斯结构多间隙耦合腔的稳定性分析

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. 关键词： 休斯结构多间隙耦合腔 耦合系数 电子注电导 稳定性

Analyses for the stability of multi-gap Hughes-type coupled cavity

In this paper, the analytical expressions of the beam-wave coupling coefficient and the beam-loaded conductance in the N-gap Hughes-type coupled cavity used in an extended- interaction klystron are derived based on the space-charge wave theory. The stability of the circuit is discussed through calculating the quality factor of the electron beam. The theoretical analyses show that with the increase of N, the stability of operating mode (2π) becomes more sensitive to the beam voltage, and that the parasitical oscillation may more easily occur and is difficult to suppress. In addition, the increase of the perveance and the decrease of the external loaded quality factor may both cause the instability of the system. The electric field intensities on the gap are greatly different among the modes 2π, π and π/2, which may be a new subject for improving the power capability and the bandwidth in klystron development.