对一种由Densiov型辐射器和四面反射镜面系统组成的准光模式变换器开展了详细的研究和设计.采用几何光学理论,分析了Denisov型辐射器的工作原理,推导了模式叠加形成高斯分布的过程.基于耦合模理论,提出了辐射器波纹波导的设计方法.针对110 GHz,TE22,6模回旋管的具体参数设计和优化了辐射器和镜面系统,编写仿真程序,对波导切口处辐射场和镜面散射场进行数值模拟.计算结果表明,输出窗口处得到较好的高斯波束,高斯效率达到95.8%,功率转换效率为94.7%.

A quasi-optical mode converter for high power gyrotron,consisting of a Denisov launcher and four mirror reflectors is designed and studied.Applying the geometrical optics,the operation mechanism of the Denisov launcher is analyzed in detail and the Gauss-like field distribution achieved on the inner wall is derived.The method for designing a dimpled wall launcher is proposed based on coupled mode theory.As an example,the launcher and mirror parameters are selected and optimized for a 110 GHz,TE22,6 mode gyrotron.Finally,a simulation code is developed to calculate the field distribution at aperture or on the mirrors.Numerical result indicates that a Gaussian-like beam is obtained through the output window,which scalar content is 95.8% and the conversion efficiency of the system is 94.7%.