一种行波管高效率输能匹配结构的场分析

行波管的输能结构性能直接影响整管的效率与工作带宽,对输能结构的阻抗进行调匹配是十分必要的,一种实用的方法是在螺旋线末端加一个匹配筒来调匹配,但这种方法在理论层面还缺乏深入的研究。本文设计了一个带匹配筒的螺旋线行波管同轴型输能结构,用HFSS软件计算了引入匹配筒前后输能结构中的电磁场分布,从场的角度分析了匹配筒在输能结构中的作用机理,并给出了调匹配时应注意的条件。进一步,在优化匹配筒结构的基础上拉松末端两圈螺旋线,在12~18GHz的频段内实现电压驻波比低于1.23,对于行波管输能结构的设计有一定的参考意义。

Field Analysis of a High Efficiency Energy Transmission Matching Structure for Traveling Wave Tubes

A coaxial energy transmission structure of helical traveling wave tube is designed with HFSS software.The transmission performance is improved by loading a matching cylinder at the end of helix.The distributions of electromagnetic field in the energy transmission structure before and after the introduction of matching cylinder are obtained by observing the cross sections at different locations of the energy transmission structure.The principle of improving the transmission performance by using the matching cylinder is explained from the field point of view,and the conditions that should be paid attention to in impedance matching are given.Furthermore,the last two coils of helix is loosened on the basis of optimizing the structure of matching cylinder,and the VSWR is less than 1.23 in the frequency range of 12~18 GHz.The analysis result has certain reference for traveling wave tube design.