基于X射线LIGA技术的太赫兹行波管研究

High power and wide bandwidth miniature Terahertz (THz) vacuum electronics amplifiers have very important applications in the military and civil fields. However, the fabrications of low attenuation high accuracy beam-wave interaction high frequency structures(HFS) are the key technologies of manufacture THz devices. In order to solve the difficulties of fabrications, a novel method of X-ray LIGA technology is presented to fabricate the fine performances HFS. Comparing with the other methods, the X-ray LIGA has some advantages, such as the larger depth-width ratio, the minimum size reaching 0.2um, the surface roughness less than 30nm and the fine repetitions. Through the series break of key technologies, such as the design of high compression ratio electron optics system, the novel methods of bury wires and fine electroform for X-ray LIGA technologies, the assemble technologies of high concentricity and linearity for miniature electron gun and micro HFS, the regularity of micro HFS fabricated by X-ray LIGA is built, and sextuple space assemble and laser collimation systems are constructed. The THz traveling wave tube will be manufactured, which operates at the frequency larger than 300GHz and output power exceeding 1W with bandwidth 5-10GHz. The achievements obtained from this project will benefit to the developments of high frequency wide bandwidth THz sources with the supply of basic theory and the supports of fabrications technologies，the progresses and applications of THz sources will be improved.

高功率宽频带小型化太赫兹真空电子放大器在军民领域具有重要的应用前景，然而制备高精度低损耗注-波互作用高频系统是研制该器件的技术瓶颈。为了解决机械制备太赫兹器件微高频结构精度低损耗大的技术难点，本项目提出X射线LIGA技术制备微高频结构的方法。相比于其它加工途径，该方法具有大深宽比、可实现最小尺寸为0.2μm、结构表面粗糙度优于30nm以及工艺重复性好等优点。通过突破高压缩大长径比电子光学系统设计、X射线LIGA技术中的埋丝工艺和精密电铸、小尺寸电子枪与微细高频结构的高同心度与直线度等关键技术，形成高精度低损耗微细高频结构制备规范，建立六维空间和激光准直装配系统，研制出频率大于300GHz输出功率大于1W带宽5-10GHz的太赫兹行波管。该项目研究成果对研制高频率宽频带太赫兹源可提供理论指导和技术支持，推动太赫兹源的发展与应用。

在太赫兹频段，高频慢波系统的尺寸变得越来越小，精度要求也越来越高，特别是对于300GHz以上真空功率行波管的高频结构，传统加工工艺已不能满足要求，必须采用现代微细加工方法来实现。为此项目申报单位中科院空天院联合中科院高能所，开展X-LIGA技术折叠波导高频结构的真空太赫兹行波管研究，通过突破系列关键技术，形成微细高频结构制备技术规范，研制出了中心频率340GHz、带宽20GHz连续波功率大于1W的太赫兹功率模块。此外，在开展340GHz太赫兹功率模块研究的基础上，开展了220GHz连续波行波管的研制，获得了27W、带宽6GHz的连续波输出功率，增益为29.5 dB。. 通过本项目的研究，一方面突破X射线掩模制作、LIGA技术深度光刻工艺、电铸折叠波导微结构工艺等技术瓶颈，解决利用X射线LIGA技术制备太赫兹行波管折叠波导微细高频结构制造的技术难点，制备出高频通道偏差小于2μm、结构侧壁粗糙度优于30nm的折叠波导高频结构，形成X-LIGA技术制备微细高频的规范。另一方面，将该先进方法制备的微细高频结构应用于太赫兹行波放大器，解决电子光学系统与微细尺寸高频结构高同心度装配的技术难点，掌握太赫兹器件制备的系列关键技术，研制出中心频率340GHz、带宽20GHz连续波功率大于1W的太赫兹功率模块。促进真空太赫兹源的应用，推动太赫兹科学与技术的发展。