140 GHz螺旋波纹波导小回旋行波放大器的研究

Research on 140 GHz Little-Orbit Helix Corrugated Waveguide Traveling Wave Amplifier

针对140 GHz回旋行波管,采用三折螺旋波纹波导作为慢波结构,通过色散特性分析优化螺旋波纹波导结构参数,达成了抑制模式竞争和扩展带宽的目的;依据布拉格衍射机理设计了输入耦合器,能够确保电子束有效流通以及信号稳定输入,且在136.5~144 GHz范围内,S_(21)>-0.5 dB。以小回旋电子注为激励源对该螺旋波纹波导回旋行波放大器进行了PIC仿真,当输入信号的频率为140 GHz、功率为50 W时,输出信号功率为223 kW,增益为36.49 dB;在134~142 GHz的频率范围时,输出功率在113~223 kW之间,3 dB带宽大于8 GHz。本文将螺旋波纹波导结构应用于140 GHz并取得了高增益和大带宽,对后续在更高频率的研究和工程应用具有较高的参考价值。

Three-folded helix corrugated waveguide is used as the slow wave structure for 140 GHz gyrotron traveling wave amplifier.The structure parameters of the helix corrugated waveguide are optimized according to the analysis of dispersion characteristics,so as to restrain the mode competition and expand the bandwidth.According to Bragg diffraction theory,an input coupler is designed to ensure the effective flow of the electron beam and the stable input of the signal.In the range of 136.5~144 GHz,the S_(21) parameter is greater than-0.5 dB.PIC simulation of the helix corrugated waveguide gyrotron traveling wave amplifier is carried out with a little-orbit gyrotron electron beam as the excitation source.When the input signal frequency is 140 GHz and the power is 50 W,the output signal power is 223 kW and the gain is 36.49 dB.In the frequency range of 134~142 GHz,the output power range is of 113~223 kW,and the 3 dB bandwidth is above 8 GHz.Employing of helix corrugated waveguide structure in 140 GHz frequency can achieve high gain and wide bandwidth,which has a high reference value for subsequent research and engineering applications at higher frequency.