多电子注高次模折叠波导高频结构的太赫兹行波放大器机理研究

High power and wide bandwidth Terahertz (THz) sources have very important applications in the military and civil fields，however, the fabrication of micro high frequency structure is the key problem for the development of high power wideband width terahertz source. In order to solve the problems of difficult manufacture and low power capacity for the miniaturized THz source, which is resulted from the shift operation frequency with the decreasing of vacuum component physical size, we propose a novel cascade overmoded high frequency beam-wave interaction system driven by multi electron beams. Compared with the conventional folded waveguide structure, the physical size is remarkably enlarged, which can decrease the difficulties of manufactured high frequency structure, welding and assembling, and increase the power capacity. The output power can be enhanced. Moreover, the efficiency can be improved for the interactions of multi electron beams with high modes in the cascade overmoded structure. Through the theoretical studies, PIC simulation and experimental performances on the novel beam-wave interactions, we explore the mechanism of THz amplifier realized by the interaction of cascade overmoded higher mode with multi electron beams, and propose the methods of suppressed non operation modes and oscillations, research on the converter of transition modes and high transmission pill-box window, reduce the loss of THz wave during the transmission, analysis the effects of transverse magnetic field and multi electron beam on the focusing of electron beam, then development the multi electron beam, conduct the experiment of multi-beam folded waveguide. Then we grasp the key technologies and method of development high power THz source. By conducting the researches, we develop the multi-beam higher mode folded waveguide traveling amplifier operates at the frequency 0.216THz, output power exceeds 50W and with the bandwidth greater than 5GHz. The achievements gain in the project including the theoretical and technologies will benefit on the developing high power terahertz source.

高功率宽频带THz波放大器在军民领域具有广泛应用前景，然而微细高频结构的制备是研制该器件的技术瓶颈。为了解决高频系统难于制备及功率容量低的技术难点，本项目提出多电子注驱动高次模折叠波导的注-波互作用系统。采用该系统可显著增大高频结构物理尺寸，降低高频结构制备及装配对中的技术难度，提升功率容量；相比于单注，采用多电子注与高次模相互作用可提高效率，增加输出功率。通过理论分析、粒子模拟及实验研究，探讨多注与高次模互作用实现THz波放大的机理，提出抑制折叠波导中非工作模式及振荡的方法；研究高次模式变换器和高透过率输能窗降低功率损耗与反射；分析横向磁场和多注对聚焦特性的影响，研制出多注电子光学系统；开展多注过模结构实验研究，掌握发展高功率宽频带THz源的方法及关键技术，研制出频率0.216THz，功率大于50W，带宽大于5GHz的多注太赫兹行波放大器。该成果对发展高功率THz源可提供理论和技术指导。

高功率宽频带THz波放大器在军民领域具有广泛应用前景，然而微细高频结构的制备是研制该器件的技术瓶颈。在国家自然科学基金资助下，本项目针对太赫兹真空电子器件功率容量低、高频结构难于加工与制备成型的技术难点，提出多电子注与过模级联折叠波导高次模相互作用的太赫兹行波注-波互作用系统。通过开展高次模式与多电子注的注-波互作用机理研究，分析过模级联高频结构的模式分布、结构参数以及衰减器等对放大器增益及输出功率等性能的影响；研究过模折叠波导中基模工作与产生振荡的机理，提出抑制非工作模式的方法与优化的衰减器结构，突破过模结构中抑制振荡的技术难点；开展高次模折叠波导模式变换器的研究，掌握高透过率输能窗设计与制备的关键技术；突破太赫兹波段多电子注电子光学系统的设计与制备的技术难点，攻克太赫兹波段高频结构制备与成型的技术瓶颈，研制出频率0.216THz、输出功率大于60W、带宽大于6GHz的太赫兹行波放大器，掌握研制高功率宽频带太赫兹真空电子放大器的关键技术基础。.本项目执行过程中，获得军队科技进步二等奖1项，最佳论文奖3项，及突出贡献奖1项。依托本项目，培养了6位硕士研究生，2位在职博士生。在国内外学术合作交流方面，本项目共参加会议39人次，其中国际会议14次，国内会议25次，特邀报告国际9次，国内5次，作为大会联合主席1次，执行主席1次，分会主席/主持4次，获得最佳论文奖3次。发表论文47篇，其中SCI收录6篇，EI收录28篇。