微波器件微放电阈值计算的蒙特卡罗方法研究

Monte-Carlo method of computing multipactor threshold in microwave devices

为了精准快速地计算微波器件中微放电效应的阈值,在传统蒙特卡罗方法的基础上,提出了三种不同的蒙特卡罗方法,分别对二次电子的初始能量、出射角度和初始相位等参数进行随机,结合四阶龙格-库塔法和Furman模型计算电子的运动轨迹和单次碰撞产生的二次电子发射系数,然后应用不同的方法计算有效二次电子发射系数作为微放电效应的判据.以平板传输线TEM模式为研究对象,采用四种不同的蒙特卡罗方法计算微放电阈值,并与统计模型结果进行对比.结果表明单电子-多碰撞蒙特卡罗方法误差最小,而且稳定性最好.

In order to find a rapid and accurate numerical method to compute the multipactor threshold in microwave device, three enhanced Monte-Carlo（MC） methods are proposed which are single particle-multiple collision MC, multiple particle-single collision MC and multiple particle-multiple collision MC method. The three MC methods all give the random nature of the secondary electrons, including their initial energies, phases and angles. And in all of the methods,the electron trajectory is computed with Runge-Kutta method and the secondary electron yield（SEY） per collision is computed with Furman model. The effective SEY is taken as the criterion to judge whether multipactor occurs, the definition of which is a little different from those of the three MC methods. As a verification, the multipactor in a parallel plate transmission line is investigated with the presented MC methods and the traditional MC method. The numerical results of the four MC methods are compared with the results of the statistical theory. It is demonstrated that the single particle-multiple collision MC method has the smallest error and the best stability.