大功率速调管中输出腔影响着整管的效率和峰值功率。为了提高效率和峰值功率，本文对工作在 X波段的同轴多注速调管双间隙输出腔结构进行研究，通过理论结合仿真优化，得出合适的双间隙输出腔结构。最后与单间隙结构进行对比，证实双间隙输出腔可以提高输出腔的特性阻抗，降低间隙电场，展宽输出带宽。

Output cavity has great impact on the efficiency and peak power of high-power klystron. To increase the peak power and improve efficiency, the double-gap coaxial output cavity in the X-band high-power multi-beam klystron is studied. An applicable structure can be achieved with parameter optimization, based on the theoretical calculation. With comparison of one-gap output cavity，it is confirmed that double-gap coaxial output cavity can increase the R/Q，decrease electric field of cavity gap， and extend bandwidth.