毫米波行波管电子光学系统的设计

 利用基于虚边界元法的VBGUN程序和基于边界元法的MOM程序，对一折叠波导毫米波行波管的电子光学系统进行了设计。设计过程中使用计算相关性系数的方法调节参数，通过计算敏感性系数以考察加工误差带来的影响。设计过程显示：低导流系数、小束腰、高压缩比的毫米波电子枪的层流性与电极尺寸相关性很大，易受到加工误差的影响；聚束系统的设计难点在于轴上峰值磁感应强度要受到漂移管半径的限制，这一点可以通过提高工作电压和降低电流来平衡，因此它的设计必须与慢波结构的设计同时进行。

Design of electron optics system of electron gun for millimeter-wave TWT

An electron gun and a magnetic-focus system for folded waveguide millimeter-wave traveling wave tube(TWT) were designed by electron gun code(VBGUN) based on visual boundary element method and magnetic field code(MOM) based on boundary element method.A definition of relative coefficient was used to optimize parameters,and a sensitive coefficient was defined to review the effect of fabrication-errors.The design results show that this kind of gun is easily affected both by the shape of the electrodes and the fabrication-errors.The maximum magnetic field on axis is limited by the dimension of the slow wave structure.This is the main problem for the focus system design of the folded waveguide TWT,which can be solved by augmenting the working voltage or decreasing the beam current.Consequently the electron optics system design must be synchronized with the slow wave structure.