基于自聚焦的赝火花多带状电子注高阶过模太赫兹返波管关键技术研究

In order to overcome the technical problems restricting the output of high power for traditional terahertz vacuum electronic devices, such as low power capacity, small current participating in the beam wave interaction, and large difficulties of the focusing of the electron beam with high transmission rate, a high order overmoded terahertz backward wave oscillator based on self-focused pseudospark-sourced sheet electron beams is proposed. It is a competitive terahertz radiation source with high power. Stable operation of the high order mode, the self-focusing of the pseudospark-sourced multiple electron beams and the beam-wave interaction in a plasma environment are the key problems urgently needed to be solved. This project will study the mode competition mechanism and high-order mode coupling output mechanism. To build a physical model of a high-order overmoded high-frequency system with stable operation, it is proposed to destruct the electric field distribution by loading metal structures, thus suppressing the low-order mode, and to extract the high-order mode by adopting a structure with power coupling function and mode transformation characteristics. And the experimental verification will be carried out. In order to clarify the self-focusing mechanism of the pseudospark-sourced multiple electron beams and the beam wave interaction mechanism under the plasma environment, the self-focusing phenomenon and the beam-wave interaction characteristics will be studied by making the plasma be equivalent to a dispersive dielectric or ionizing the inert gas with low pressure in the simulation model. This project will explore this high-power terahertz source with good development prospects, achieving theoretical foundation and technical reserve for the future research of this device.

为了克服传统太赫兹电真空器件功率容量低、参与注波互作用电流小、高流通率电子注聚焦难等制约大功率输出的技术难题，创新性地提出了一种基于赝火花放电的等离子体自聚焦多带状电子注高阶过模返波管，它是一种有竞争力的大功率太赫兹源。高阶模的单模稳定工作、等离子体环境下的赝火花带状多注自聚焦和注波互作用是该管亟需解决的关键问题。本项目将对模式竞争机理和高阶模耦合输出机理进行研究。提出通过金属结构破坏电场分布来抑制低阶模，利用兼具功率耦合和模式变换特性的结构来输出高阶模，以构建稳定工作的高阶过模高频系统物理模型，并进行实验验证。通过将等离子体等效为色散介质、在仿真模型中电离低压惰性气体等方法，对等离子体环境下的自聚焦现象和注波互作用特性进行理论研究和模拟仿真，以阐明等离子体环境下的赝火花带状多注自聚焦机理和注波互作用机理。本项目将探索这种具有发展前景的大功率太赫兹源，为器件研发奠定理论基础和技术储备。

太赫兹技术在高精度雷达、高数据率通信和电子对抗等诸多军民应用领域有着广泛的应用前景。大功率太赫兹源的匮乏是制约太赫兹技术发展的瓶颈技术之一。本项目提出了一种基于赝火花放电的等离子体自聚焦带状多电子注的高阶过模返波管。对高阶过模返波管的关键零部件，包括输出窗、功率耦合结构、模式变换器、慢波结构等，展开了理论分析、仿真设计、微加工制造、实验测试验证。提出了3款新型的高阶过模功率耦合结构和2款新型的高阶过模平面慢波结构（高阶过模交错栅、高阶过模正交栅），能够实现高阶过模带状多注器件的功率耦合及稳定注波互作用（竞争模有效被抑制）。各个零部件的冷腔测试实验证实了设计方案的可行性。对赝火花电子注等离子体效应展开了理论研究。理论推导了赝火花电子注等离子体等效介质的复介电常数，并将其应用于高频系统电磁特性（色散特性、传输反射特性）及注波互作用特性（输出功率、频率等）的分析。研究表明：相比于真空填充的返波管，等离子体填充的返波管输出功率将略微下降，谐振频率将略微提升，且带宽将略微扩宽。开展了赝火花放电的实验测试，测得了电压电流曲线，电子注峰值电流达15A。本项目设计的两款高阶过模带状双注返波管分别在12.3GHz （225-237.3GHz）/12.8 GHz (224.0-236.8 GHz)可调谐频带内输出了>100.1W/>154.9W功率。本项目的开展为赝火花电子注器件及高阶过模带状多注器件的研发奠定了理论基础和技术储备。