【作者】 臧杰锋；

【导师】 刘庆想；

【作者基本信息】 西南交通大学 ， 电磁场与微波技术， 2010， 博士

【摘要】 渡越辐射器件具有结构简单,效率高等特点,因此它们在众多的高功率微波源中具有特殊的吸引力,但是由于传统的轴向渡越辐射器件的阻抗较高(几十甚至上百Ω),器件的峰值功率受到限制。在高功率微波源低阻抗、高功率、高效率的发展需求下,如何降低器件的阻抗,提高输出功率成为渡越辐射器件的研究重点内容。利用径向结构空间电荷效应小、空间电荷限制流大的特点,基于三腔渡越时间振荡器,提出了一种新型低阻抗高功率微波器件——径向三腔渡越时间振荡器(栅网结构),理论效率35%,CHIPIC程序粒子模拟获得了平均功率7.4GW的微波输出,束波互作用效率27.4%,阻抗7.5Ω；考虑到径向结构中的环形栅网加工困难、且会限制器件的功率容量,提出了边加载结构径向三腔渡越时间振荡器,粒子模拟给出的束波互作用效率达33.3%；又根据三维理论的研究,提出了改进型径向三腔渡越时间振荡器,理论效率超过50%,粒子模拟效率达47.4%。本文主要从理论分析和粒子模拟两方面深入细致地研究了径向三腔渡越时间振荡器的基本原理。所做的主要工作和贡献如下：一、提出了径向三腔渡越辐射振荡器包括栅网结构、边加载结构(含改进型边加载结构)。二、采用近似手段首次将Floquet定理应用到径向结构,并对径向三腔渡越时间振荡器包括栅网结构和边加载结构的慢波系统进行高频特性分析,获得了色散方程。以栅网结构为例,对色散方程进行了数值求解和误差分析,获得了该方法适用范围。三、将一维理论应用于径向三腔渡越时间振荡器的理论分析,并获得了一维理论的适用范围。四、建立了三维理论并对径向三腔渡越时间振荡器进行了全面分析,获得了电子束电压、调制系数、谐振腔径向长度、电子束位置与束波互作用效率的关系,并研究了电子束运动轨迹。理论表明边加载结构的束波互作用效率超过50%。五、利用CHIPIC程序对径向三腔渡越时间振荡器进行了详细的模拟研究,研究了器件的效率、频率与电子束参数和谐振腔结构参数的关系,获得了对实验有指导意义的结果。更多还原

【Abstract】 Compare to numbers of high power microwave (HPM) sources, the transit time oscillators have the special merits, such as, simple structure, high efficiency and so on. These characters make the transit time oscillators been given most attention by the studies. But usually, the traditional axial transit time oscillators have a character of high impedance which restricts the output wave power seriously. And so under the uptrend of lower impedance, high efficiency and high power, how to improving the impedance merit and obtain higher power become the keystone of the transit time oscillators.By the base of the three-cavity transit time oscillator, and considering the merits of the radial structure such as the small space charge offect and big space charge restricting current, A new kind of low impedance HPM oscillator named radial three-cavity transit time oscillator is brought forward. Through the PIC simulation, the oscillator gives an output wave of 7.4GW, and the impedance 7.5 Q, and the efficiency 27.4%. In order to improve the highest power capacity, and depress the difficulty of the cure, the side-appending configuration is also brought forward with an efficiency of 33.3% by the PIC simulation. And through the 3D theoretic analysis, an improved side-appending configuration is brought forward, and the efficiency enhanced to 47.4%. In this dissertation, we will comprehensively study the radial three-cavity transit time oscillator by the theoretic analysis and the PIC simulation. Main jobs and contribution done by this dissertation are as follows:First, the structures of the radial three-cavity transit time oscillators, including the foil structure, the side-appending structure, and the advanced side-appending structure are brought forward.Second, the Floquet theory is firstly applied to the radial structure by an approximate method. And under the theory, the high-frequency merits of the cavities including the foil structure and the appending structure are analyzed, and the dispersive equations are obtained. For illustration, the dispersive equations of the foil structure are solved by the numerical method, and errors are analyzed, and the applicable additions are given.Third,1-D theory is applied to explain the process of the co-action of the beam and the cavity, and the applicable additions are given.Forth, A 3-D theory is constructed. Using the 3-D theory, full analysis to the radial three-cavity transit time oscillator has been done. The volts of the beam, the modulation coefficient, the length of the cavity in the radial and the beam location, are analyzed how to infecting the co-action efficiency. And also the electrons tracks are given. Through the theory, we know that, the advanced side-appending structure indeed has a higher efficiency (higher than 50% by theory).Fifth, comprehensive simulations have been done to the radial three-cavity transit time oscillator, and the infections of the beam parameters and the cavity parameters to the efficiency have been analyzed. And some valuable results to the experiments are obtained.更多还原