太赫兹新型正弦波导大功率行波放大器的理论与实验研究

As the heart of the high-end electronic equipments such as modern radar, electronic countermeasure and satellite communication system, the wide-band traveling wave tube(TWT) operating in the millimeter wave and terahertz frequency range with high efficiency and high power, in which the slow wave structure(SWS) basically determines the working, has been becoming a research priority in the development of vacuum electronics. In this proposal, we will carry out theoretical and experimental studies on the terahertz traveling wave amplifier based upon the novel sine waveguide slow wave structures (SWS). First, the novel large-sized sine waveguide SWSs with lower RF loss and higher interaction impedance will be construed by using the mode selection mechanism in the overmoded sine waveguide with non-uniform period；Second, the slow wave properties and beam-wave interaction properties of the new SWS are analyzed by taking the surface loss into the account；Then, in order to increase the output power at terahertz band, the design of a high power novel sine waveguide traveling wave tube, in which an electron beam with a larger current is employed, is made by thoroughly investigating the effects of the structures parameters and electron beam parameters on the operation of the tube. In the TWT amplifier design, the center frequency is 220GHz/380GHz, bandwidth is 20GHz and the output power is 60W/15W. Finally, the experimental study on the RF loss and TWT amplifier are carried out. All of these results will provide a strong physical and technical foundation for the high power high efficiency TWT amplifier operating at short millimeter wave and terahertz band.

高效大功率宽带毫米波太赫兹行波管是雷达、对抗和卫星通讯等高端电子装备的心脏，慢波结构始终是制约行波管发展的技术瓶颈，是真空电子学研究的热点和难点。本项目将对新型正弦波导行波放大器开展理论和实验研究，通过分析有损耗情况下，非均匀周期过模正弦波导中模式选择的物理机制，构建出新的大尺寸、低损耗、高耦合阻抗正弦波导慢波结构；建立新型正弦波导结构的高频特性理论和注波互作用理论；系统地分析慢波结构参数和电子注参量对慢波特性和行波管输出特性的影响，提出降低慢波结构高频损耗的途径和增大器件互作用效率、提高输出功率的方法，形成太赫兹行波管新方案（中心频率220GHz/380GHz，带宽20GHz, 输出功率大于60W/15W），并进行高频结构的损耗特性和大功率输出特性的实验验证；为提高短毫米波、太赫兹行波放大器的效率和输出功率奠定物理与技术基础。

本项目对新型正弦波导行波放大器开展理论和实验研究，通过分析有损耗情况下，非均匀周期过模正弦波导中模式选择的物理机制，构建出新的大尺寸、低损耗、高耦合阻抗正弦波导慢波结构；建立新型正弦波导结构的高频特性理论和注波互作用理论；提出了降低慢波结构高频损耗的途径和增大器件互作用效率、提高输出功率的方法，形成太赫兹行波管新方案（中心频率220GHz，带宽20GHz, 输出功率大于60W）；研究了带状电子注电子光学系统中电子注的产生和聚焦方法。获得了多种聚焦方法，包括低磁场PCM聚焦以及磁场和静电场混合聚焦的新方法；带状电子注流通率大于92%；开展了W波段正弦波导行波管热测实验工作，实测结果表明当行波管工作在96GHz时，有最大输出功率54.5W，增益大于18.5dB，热带宽10GHz，验证了正弦波导的宽频带工作特性,为发展大功率、高效率的新型行波管奠定了理论与技术基础。