W波段分布作用速调管的设计和实验研究

基于运动学理论、感应电流定理和电荷守恒定律,分析了分布作用谐振腔的渡越时间效应,推导了各个谐振腔工作于π模的电子注与微波之间的能量转换系数、电子负载电导和电子负载电纳,计算结果显示采用分布作用谐振腔有利于提高速调管的工作效率.利用三维电磁仿真软件,设计了一款工作于W波段的分布作用速调管.完成了速调管的加工和封接,搭建了测试平台,开展了相关实验研究.实验结果显示,当电子注电压20.8 kV,电流0.3 A,输入功率30 mW时,在中心频率95.37 GHz处,得到了175 W峰值脉冲输出功率,电子效率2.8%,增益34.6 dB, 3 dB带宽大于90 MHz.

Design and experimental analysis of W-band extended interaction klystron amplifier

Beam loading is an important parameter in extended interaction klystron, which can be used to analyze the influence of beam on resonant frequency and ohm loss Q, and study the match condition between input cavity and external power source, etc. Based on the kinematical theory, law of induce current, principle of charge conservation under the small signal condition, and one-dimensional (1D) mode, the transit time effect of electron in \${\text{π}}$\ mode standing wave electric treld in a multiple-gap resonator is analyzed, and the expressions of electron load conductance and electron load susceptance in the multiple-gap resonator are presented. The results show that the electron load conductance of extended interaction cavity can change in a bigger extension than that of traditional single gap cavity, which means that the loaded Q of extended interaction cavity can be adjusted in a bigger extension to realize a desired Q. And the results also show that the electron load susceptance of extended interaction cavity can change in a bigger extension than that of traditional single gap cavity, which means that the loaded frequency of extended interaction cavity can also be easily adjusted to a desired value. The influence of gap number on the power exchange between beam and microwave is also investigated, which shows that the maximum power exchange between beam and microwave electric field increases with the number of resonator gaps increasing, and so does the efficiency of klystron. A W band extended interaction klystron amplifoer is designed by the above theory analysis and three-dimensional (3D) PIC code. The simulation results show that when beam voltage is 20.8 kV, current is 0.28 A, input power is 30 mW at a frequency of 94.77 GHz, the extended interaction klystron can produce 443 W output power. The responding electron efficiency is 7.6%, the gain is 41.7 dB, and the 3 dB bandwidth exceeds 150 MHz. The extended interaction klystron is machined and tested, and the experimental results show that the maximum output power of 175 W is obtained with a beam of 300 mA, a voltage of 20.8 kV, and an input microwave power of 30 mW at a frequency of 95.37 GHz in a magnetic field of 0.62 T. The responding electron efficiency is 2.8%, the gain is 34.6 dB, the 3-dB bandwidth exceeds 90 MHz. This study is meaningful for designing and developing greater power extended interaction klystrons.