Ka波段螺纹波导回旋行波管大回旋电子枪的研究与设计

Design of CUSP Gun for Ka-Band Helical Waveguide Gyro-Traveling Wave Tube

从拉氏方程出发,推导了大回旋电子枪(CUSP)的理论,得到了用于Ka波段螺纹波导回旋行波管大回旋电子枪的基本参数。通过CST-Particle Stuido 3D粒子模拟软件,分析了不同参数对大回旋电子枪横纵速度比、速度离散的影响,理论计算与粒子模拟结果相互吻合。研究发现,影响大回旋电子注质量的主要因素是阴极所处的位置,所以文中重点分析了阴极装配误差对电子注质量带来的影响。通过将理论与仿真设计相结合,最终得到一种工作电压70 k V,电流5 A,速度比1.0的大回旋电子枪,满足Ka波段螺纹波导回旋行波管对高质量电子枪的要求。

The generation of a large orbit CUSP electron beam for ka-band helical waveguide gyro-traveling wave tube （TWT） was modeled, analyzed by solving Lagrangian dynamical equations, and simulated with CST-Particle Studio 3D PIC software. The impact of the major factors, including the gun structure, anode voltage, cathode＇ s position and align- ment eccentricity, magnetic fields of cathode and beam-wave interaction, and assembly tolerance, on the velocity-ratio and velocity-spread of the beam was investigated. The results show that the axial position and alignment eccentricity of the cathode strongly affect the gun＇ s performance. Good agreement was found between the analytical and simulated results. Based on the analyzed and simulated results, an optimized CUSP gun was designed. Operating at a voltage of 70 V and a current of 5 A, the proposed CUSP gun is capable of generating an electron beam with a velocity-ratio of 1.0 and a low velocity-spread of 2 % - 5 %, satisfying well the requirements of the helical waveguide gyro-TWT.