面向太赫兹真空电子器件应用的基于微加工技术的矩形环-杆结构慢波特性研究

Characteristics of Micro-Fabricated Rectangular Ring-Bar Slow Wave Structure for THz Vacuum Electron Devices:A Simulation and Theoretical Study

提出了一种基于微加工技术的行波管矩形环-杆慢波结构的简便等效电路分析方法,采用准-TEM近似方法得出了其色散方程和耦合阻抗表达式,并数值计算了复色散方程和耦合阻抗。理论计算结果和3D电磁仿真软件HFSS的结果吻合得很好。数值计算结果表明:结合介质基底后,慢波结构的色散变弱,相速降低,带宽变宽,耦合阻抗却在降低。最后,通过和对应的矩形螺旋线慢波结构进行了比较,得出了该慢波结构高增益和高功率的特性。作为一种平面结构,矩形环-杆慢波结构可以结合微加工技术并应用到毫米波甚至THz波段的紧凑行波管领域。

The dispersion and coupling impedance,of the rectangular ring-bar slow wave structure（ SWS） micro-fabricated on dielectric substrates of traveling-wave tube（ TWT） for THz vacuum electron devices,were mathematically formulated with equivalent circuit model,theoretically analyzed,empirically simplified in quasi-TEM approximation and numerically simulated with software HFSS. The calculated and simulated results were in good agreement. The simulated results show that the dielectric material filled in the rectangular ring-bar SWS has a major impact. For example,the dielectric material significantly decreased the dispersion and phase velocity but considerably increased the bandwidth. In addition,the rectangular ring-bar slow-wave structure（ SWS） was found to outperform the rectangular helix SWS because of higher gain and larger output power. We suggest that the simulated results may be of some technological interest in micro-fabrication of compact TWTs working in millimeter and sub-millimeter wave ranges.