A 0.33-THz second-harmonic frequency-tunable gyrotron

Dynamics of the axial mode transition process in a 0.33-THz second-harmonic gyrotron is investigated to reveal the physical mechanism of realizing broadband frequency tuning in an open cavity circuit. A new interaction mechanism about propagating waves, featured by wave competition and wave cooperation, is presented and provides a new insight into the beam-wave interaction. The two different features revealed in the two different operation regions of low-order axial modes(LOAMs) and high-order axial modes(HOAMs) respectively determine the characteristic of the overall performance of the device essentially. The device performance is obtained by the simulation based on the time-domain nonlinear theory and shows that using a 12-kV/150_(-mA) electron beam and TE_(-3,4) mode, the second harmonic gyrotron can generate terahertz radiations with frequency-tuning ranges of about 0.85 GHz and 0.60 GHz via magnetic field and beam voltage tuning,respectively. Additionally, some non-stationary phenomena in the mode startup process are also analyzed. The investigation in this paper presents guidance for future developing high-performance frequency-tunable gyrotrons toward terahertz applications.     

W波段损耗介质加载回旋返波振荡器中模式竞争的研究

本文采用自洽非线性理论模型系统研究W波段基波TE₀₁模回旋返波振荡器 模式竞争的物理机理. 通过采用特殊渐变的非谐振互作用结构和加载损耗介质抑制互作用系统中竞争模式, 从而防止系统出现非稳态振荡现象. 通过系统优化的互作用结构可以抑制竞争模式,能够稳定工作在TE₀₁模的轴向基模上. 计算表明系统输出峰值功率105 kW, -3 dB调谐相对带宽为5.4%. 这为发展应用于电子对抗、无损探测、等离子体诊断、材料处理等领域 的宽带毫米回旋返波振荡器提供了理论基础, 具有借鉴意义.     

W波段螺旋波纹波导回旋行波管注波互作用的非线性分析

本文从有源麦克斯韦方程组出发, 系统地推导了螺旋波纹波导的色散方程及非线性注波互作用理论, 数值计算结果与已有的实验报道基本相符.在此基础上,设计了W波段螺旋波纹回旋行波管, 工作电压80 kV, 工作电流5 A, 中心频率95 GHz, 3 dB带宽约4.5%, 饱和增益52 dB, 最大输出功率142 kW, 电子效率达20%-35%.最后,本文计算了电流, 电压及输入功率的改变对W波段螺旋波纹波导回旋行波管输出性能的影响.     

大动态高精度有界波电磁脉冲模拟器设计

介绍了一种精细化、连续可调的中型有界波电磁脉冲模拟器,该模拟器配置了前沿快、结构紧凑、脉冲电压调节范围宽、自动化程度高的新型高压脉冲源,实现了全系统的计算机光纤控制,解决了控制系统抗干扰问题,提升了源的模拟能力和设备的应用范围。模拟器的具体指标为:脉冲前沿约2.5 ns,半高宽约23 ns,工作空间4 m×4 m×5.8 m,输出电场强度在0.2~60 kV/m范围内连续可调。