中文摘要：

详细研究了一种用于回旋管冷测的三段式同轴谐振腔模式激励器,该模式激励器利用同轴开放腔的选频选模特性将输入的W波段的波功率转换为TE6,2模式输出。基于缓变截面波导理论,研究了同轴谐振腔激励TE6,2模式的机理;求解了同轴波导中TE模式的特征根和不均匀弦方程并得到腔体谐振频率及Q值;分析了同轴腔内外半径对谐振频率的影响;给出了W波段高纯度TE6,2模谐振腔优化设计的参数;并用电磁仿真软件对其进行仿真计算,结果表明：该谐振腔的TE6,2模式纯度达到99.51%。

英文摘要：

A novel type of three-stage coaxial mode resonator was developed for the cold test of gyrotron. The resonator is capable of changing the input W-band electromagnetic wave into TE6,2 mode because of its frequency and mode selectivity. The mechanism responsible for TE6,2 mode selectivity of the coaxial resonator was investigated based on the theory of slow-changing cross-section of coaxial waveguide. The eigenvalues of TE mode and resonance frequency were calculated. The Q-factor and amplitude distribution of the resonator cavity were obtained. The impact of the inner and outer radii of coaxial cavity on resonance frequency was studied. In addition, the W-band, high purity TE6,2 mode resonator was modeled, de- signed,and simulated with software package HFSS. The simulated results show that the mode purity of TE6,2 reaches 99.51%.