THz两级串联慢波结构研究

Design of Two-Stage Slow-Wave Structure of THz Oscillator

提出了一种基于矩形交错双光栅的两级串联慢波结构,该高频结构采用双电子注通道和一个聚焦系统,高频信号分别在两段慢波结构中工作在-1和＋1空间谐波状态。对该慢波结构的色散特性进行了模拟计算,分析了该器件工作原理。通过设计传输变换结构及两级慢波连接波导组成高频互作用电路,在295-320 GHz频率范围内获得较好的传输特性,反射系数S11〈-17 dB,传输系数S21〉-12.51 dB。利用三维粒子模拟设计的方法,在单注电流18 mA时,获得14.6 W的299.5 GHz信号输出,电子效率为1.7%。

A novel type of two-stage slow wave structure（ SWS）,for-1 and ＋ 1 harmonic modes,was developed for terahertz oscillator,based on the half-period-staggered double grating arrays,to improve the interaction efficiency and output power. The transition structure and the connecting waveguide between the SWSs were also designed. The SWS dispersion characteristics and the beam-wave interaction with two electron beams were physically modeled,theoretically analyzed,and numerically simulated with software 3-D particle-in-cell（ PIC）. The transmission losses of the whole RF structure and reflection coefficient were found to be S21〉-12. 51 dB and S11〈-17 dB,respectively. The simulated results show that the novel two-stage SWS significantly enhances the interaction efficiency and output power. To be specific,with one 18 mA electron beam,the interaction efficiency of 1. 7%,at a radiation of 0. 3 THz,results in a high output power of 14. 6 W at 299. 5 GHz. We suggest that the newly-developed two-stage SWS be of some technological interest in design of terahertz vacuum electronic sources.