双间隙输出腔开放腔的高频特性分析

 建立了S波段相对论速调管放大器双间隙输出腔开放腔的3维模型。采用时域有限差分法，通过监测激励电流源的响应计算了该双间隙输出腔的谐振频率、有载Q值、场分布以及特性阻抗，并分析了腔体结构尺寸对谐振频率、有载Q值和特性阻抗的影响。研究表明：腔体半径对开放腔的谐振频率影响很大，耦合孔尺寸对腔体谐振频率的影响较小；随着耦合孔张角增加，有载Q值逐渐减小；随着腔体半径增大、间隙的减小，腔体特性阻抗降低。研究结果可为S波段强流相对论速调管放大器双间隙输出腔的设计提供理论依据。

High frequency characteristics of double-gap output cavity

This paper presents a 3-D model for double-gap open cavity of S-band relativistic klystron amplifier.By observing the response of the current driver,the high frequency characteristics including resonant frequency,loaded quality factor(Q),field distribution and character impedance of the open cavity are calculated.The effect of the open cavity size on the resonant frequency,loaded Q value and the character impedance are discussed.The results show that the frequency mainly depends on the radius of the cavity and the loaded Q value diminishs owing to the increase of the angle of the coupling hole,and the character impedance declines due to the increase of the radius and the decrease of the gap length of the cavity.The analysis provides a theoretical basis for the design of the double-gap output cavity of S-band relativistic klystron amplifier.