利用周期结构电磁止带特性的小型化高功率太赫兹振荡器

Miniaturized high power terahertz oscillator using electromagnetic stop-band characteristics of the metal periodic structure

摘要:

高性能实用化辐射源是太赫兹应用的关键器件，利用周期结构电磁色散中的止带区域具有耦合阻抗高的特点，电子注和电磁波能够高效互作用，可以实现大功率太赫兹振荡器。带边振荡器(BO)相比于传统的返波振荡器(BWO)，可以实现大功率输出，在W波段能达到百瓦量级，太赫兹波段能达到瓦级；采用周期永磁聚焦系统，可以实现小体积轻质量；慢波结构尺寸短，结构简单；成本低，具有批量生产能力。本文提出可构建3π止带的交错子周期折叠波导慢波结构(FWG SWS)和双频双模双向带边振荡器工作机理，采用皮尔斯双阳极电子枪、周期永磁聚焦系统、金刚石输能窗以及高效率收集极，设计和研发了频率在100 GHz以上的几种带边振荡器，实现了100 GHz频段140 W的功率输出，120 GHz频段实现了30 W的功率输出，在300 GHz实现了1 W以上的功率输出。

Abstract:

High performance and practical radiation source is the key device for terahertz applications. High power terahertz oscillators can be realized by utilizing the great impedance near π, 2π and 3π stop-band which means that strong interaction can occur. Compared with the traditional Backward Wave Oscillator(BWO), the Band-edge Oscillator(BO) can achieve high power which can achieve the order of 100 W in W band and 1 W in the THz regime; can realize miniaturized device with Periodic Permanent Magnet(PPM) focusing system; can realize compact structure with Folded Waveguide Slow Wave Structure(FWG SWS) which is short in size and simple in structure; can realize low cost mass production. In this research, a stagger half-period FWG SWS and a novel operation concept for the BO with the folded waveguide are proposed. The BO is composed of Pierce-style double-anode convergent electron gun, periodic permanent magnet focusing system, diamond pill-box window and high efficiency collector. Several novel BOs above 100 GHz have been simulated, fabricated and tested, which achieved output power of 140 W at 100 GHz, 30 W at 120 GHz, and over 1 W at 300 GHz. The dispersion characteristics, design of devices and test results are described and analyzed.