【作者】 文杰；

【导师】 田扬超； 范植开；

【作者基本信息】 中国科学技术大学 ， 同步辐射及应用， 2011， 博士

【摘要】 在全面调研磁绝缘线振荡器( MILO)理论的基础上,结合器件自身工作特点,首次提出了一种可以在模式竞争时保持频率稳定的器件-单频多模MILO。单频多模MILO是一种低阻抗正交场高功率微波器件,它不仅具有MILO不需要外加磁场,体积小的优点,还具有在模式竞争下能够输出稳定频率的高功率微波(High Power Microwave,HPM)的特点。能够产生多个模式且频率单一的微波的器件是HPM的一个新兴的研究方向,首先这种器件能够避免模式竞争引起的微波频率不纯,达到更好的实验目的,同时微波远场具有多种模式的方向图特点,能够在模式竞争发生时实现大范围的辐射,而目前国内外暂无相关的研究,因此该研究在MILO研究领域具有一定的推动作用。论文提出了单频多模MILO的实现方式并建立了单频多模MILO的模型,结合冷腔和热腔的分析,优化设计出了工作在1.22GHz的一套单频多模MILO,并在现有的条件下开展了实验,对不同角度的功率密度进行了测量,最终验证了这种多种模式工作时产生单一频率的HPM的MILO的可行性。同时,论文还讨论了MILO适应环境时的一些技术,提出了两种具有特点的新型MILO。以下是论文研究的主要内容:从HPM的开始,介绍了MILO的优点、基本原理及国内外发展现状,介绍了MILO常用的研究方法,并阐述了单频多模MILO的研究意义。从MILO慢波结构入手,结合器件中束波作用机理,提出了单频多模MILO的思路。根据MILO设计时各个参数的选取方法,设计并优化了一套工作频率为1.22GHz的L波段MILO,并通过对慢波结构2维周期化实现单频多模输出。利用开放腔高频分析对单频多模MILO的可行性进行了证明,同时对其进行了3维数值模拟:在自激发引起的模式竞争和非对称条件引起的模式竞争下都能保持输出微波的频率单一。根据理论优化设计的结果加工了一套单频多模的磁绝缘线振荡器,并在现有的实验条件下建立了其实验系统,由加速器型脉冲功率源,单频多模MILO,真空系统,微波测试系统组成。利用多组极化方向相互垂直的BJ32波导同轴转换器对辐射空间不同角度的功率密度进行测定,然后通过积分计算出辐射功率和方向图,从实验上验证了这种单频多模MILO的可行性。为了满足环境需求,结合理论,数值模拟和实验研究,对L波段磁绝缘线振荡器的阴极支撑方案进行了讨论,同时对起振电压和注入电压的关系进行了分析。提出了两种新型的MILO,一种是轴向分区的双频MILO,与角向分区双频不同,它分别作用在上下两段不同周期的慢波结构的基模下,得到稳定的双频TEM模式的微波输出,频率分别为1.25GHz和1.65GHz,便于双频模式变换器的设计,实现集中辐射,同时为双频MILO设计了对应频率的TEM-TE11的模式变换器;另一种是Ku波段的MILO,相对于现阶段重点研究的L波段,能有效提高高功率微波的性能度量因子。更多还原

【Abstract】 A novel magnetically insulated transmission line oscillator-MILO with mutimodes and single frequency is put forward for the first time in the dissertation after basic theory of MILO has been generally studied. MILO with mutimodes and single frequency is an HPM (high power microwave) device with cross-field and low resistance, which does not only have the advantage of dispensing with magnetic and small volume as the original MILO, but also generate microwave with single frequency during modes competition. This kind of HPM device is a new research direction for it can make the frequency of microwave stable to achieve the experiment purpose better and its far field directional diagram has the characteristic of mutimodes, which enlarge the 3dB width and radiation area. It has a great of academic value, so I put forward hypothesis of MILO with mutimodes and single frequency, create an L-band model and prove its feasibility from high frequency analysis, PIC (particle in cell) simulation and theoretical experiment. At the same time some research of other technology of MILO and two kinds of new MILO is carried out.This thesis focuses in the following areasFirstly, the investigation of the background of HPM technology and the present development of MILO are introduced and the principle and research methods of MILO are pointed out. Then, the academic value of MILO with mutimodes and single frequency is explained.Secondly, a novel MILO which can generate microwave with stable frequency during modes competition is put forward by adjusting the SWS (slow wave structure) with the theory of interaction between electron beam and microwave. An L-band MILO with mutimodes and single frequency which works at 1.22GHz is designed based on the selecting methods of parameters of MILO structure and its high frequency analysis and PIC simulation are carried out, which proves that this novel MILO’s feasibility of stable frequency during modes competition caused by self-excitation or dissymmetrical excitation.Thirdly, a preliminary experiment of this novel MILO is carried out based on the optimized structure in simulation. Experimental system is built based on the condition in existence in laboratory, which contains pulse power supply, MILO, vacuum system and measurement system. Calibration method is also introduced. The radiation power and direction diagram are calculated by measuring the power density at different angle in spaces with BJ-32 antenna. Afterwards the feasibility of this novel MILO is proofed experimentally.Fourthly, to satisfy the environment condition, the investigation of cathode’s strut is carried out with theory simulation and experiment and the relation between starting voltage and input voltage for a MILO has also been analyzed.Fifthly, two kinds of new MILO, bf-MILO with axial partition and Ku-band MILO, are put forward, one of which has two 2 pieces of SWS with different period and cavity depth and generates stable bi-frequency TEM mode microwave of 1.25GHz and 1.65GHz. This kind of bifrequency MILO is convenient to the modes converter designing compared to the azimuthal partition ones. The other kind of MILO is a Ku-band MILO working at 13GHz, which improve the MILO’s energy metric factor (pf2) obviously comparing the L-band ones.更多还原