【作者】 张华福；

【导师】 林福民；

【作者基本信息】 广东工业大学 ， 物理电子学， 2012， 硕士

【摘要】 大功率速调管是一种基于速度调制原理将电子注能量转换成微波能量的微波真空器件,并且在宽带雷达系统、电子对抗和通信系统等领域有了广泛的应用。谐振腔是速调管放大器当前微波频段大功率高增益的主要核心部件。速调管的谐振腔可分为3类,即输入谐振腔,中间谐振腔和输出谐振腔。输入谐振腔的功能是输入外加微波信号,在谐振腔间隙上建立微波电场,调制电子注。中间腔的功能是提高速调管的增益、带宽和效率。输出腔的功能是将群聚电子注的能量转换成微波能量。谐振腔作为速调管的高频互作用电路,其特性对速调管的效率、增益和带宽的性能具有决定性的影响。在速调管工作时会有电子注穿越谐振腔,使得谐振腔的性能发生变化。而谐振腔本征值问题是电磁工程领域的一个重要课题,一方面腔体中不同模式的场型分析直接和此问题有关,另一方面,很多腔体的最优化设计又往往以该问题的求解为基础。无源情况下的各种谐振腔中谐振频率的大小,电磁场的分布,各种模式的分析都是研究这些腔体非常重要的参考。因此本文研究了电子注穿越谐振腔时对谐振腔的振荡频率和电磁场分布的影响。本文的研究内容如下：一、首先概述了速调管的结构,工作原理,发展历程,发展现状以及谐振腔的理论。二、通过区域划分,建立填充有电子注的谐振腔物理模型,在原有的波动方程的基础上,在边界匹配条件下进行推导得到了电子注区域的电磁场分布和真空区域的电磁场分布。并且通过进一步的推导,得到了T0m0模式下的特征方程。三、通过数值计算,得到了谐振腔TM010模式和TM020模式的谐振频率ω随着电子注的等离子体频率ωp的变化,并且采用了图解法求解本征值方程的方法对计算结果进行了验证。随着等离子体的频率不断增大时,谐振频率也会不断增大。当等离子体的频率为40GHz以上时,谐振腔的谐振频率变化不大。最后通过计算仿真,得到了TM010模式和TM020模式的谐振腔的电磁场分布随着等离子体频率的变化情况,并且对其进行了分析研究。由研究结果得知,当等离子体的频率超越谐振腔的谐振频率时,谐振腔内的电磁场分布会有很大的变化,这对于大功率速调管的稳定性将有着重要影响。电子注对谐振腔的影响规律适用于其它类型的大功率微波源,所以对于速调管和其它类型微波源的研制也具有重要的参考价值。更多还原

【Abstract】 The high power klystron is a microwave vacuum device based on the principle of velocity modulation converting the electron beam energy to the microwave energy, which is a wide range of applications in areas such as broadband radar systems, electronic warfare and communications systems.The resonant cavity is the main core components of the klystron. The klystron resonant cavity can be divided into three categories, the input cavity, the middle of the cavity and the output cavity.The function of the input cavity is inputing the microwave signal, and producing microwave electric field in the cavity gap as to modulate electron beam. The function of the middle cavity is to improve the gain, bandwidth and efficiency of the klystron. The function of the output cavity is to convert the cluster electron beam energy into microwave energy. As a high-frequency interaction circuits of the klystron, the resonant cavity’s characteristics have a decisive impact on efficiency, gain and bandwidth performance of the klystron. When the klystron works, the electron beam will through the resonant cavity, which makes the resonant cavity’s performance change. The eigenvalue problem of the resonant cavity is an important topic of electromagnetic engineering fields. On the one hand, the different modes analysis of the cavity field is directly related to this issue, on the other hand, the optimization design of many cavity is often based on the solving of the problem. The size of the resonant frequency, the distribution of the electromagnetic field and the analysis of the various modes are the most important reference when studying these cavities. This article studies the influence of the resonant frequency and electromagnetic field distribution in the resonant cavity traversed by electron beam. The contents of this paper are as follows.Firstly, we briefly describe the structure, working principle and the the development of the klystron as well as the theory of the resonant cavity.Secondly, through zoning, a physical model of the resonant cavity filled with the electron beam was established. On the basis of the original wave equation, the electromagnetic field distribution of the electron beam region and the vacuum region are educed in the boundary matching conditions. And the eigenfrequency equations of the TM0m0mode are educed by further educing.Thirdly the resonant frequency of the TM010mode and the TM020mode changes with the plasma frequency can be got by calculating. And uses a graphical method for solving the eigenvalue equation to verify the calculation results. The results show that with the increasing of the plasma frequency, the resonant frequency will continue to increase. When the plasma frequency exceed40GHz, the resonant frequency o changes little. Finally, The resonant cavity’s electromagnetic field distribution of the TM010mode and the TM020changes with the plasma frequency also can be got by simulating. When the plasma frequency increases, it will make the electromagnetic field distribution change. And the results show that, when the plasma frequency exceeds the resonant frequency, the electromagnetic field distribution of the resonant cavity will change greatly, which will have an important impact on the stability of the high power klystron. The impact of the law of the resonant cavity filled with electron beam also applies to other types of high-power microwave source. So it will have important reference value for the development of the klystron and other types of microwave sources.更多还原