| Traveling wave tube（TWT）is a kind of vacuum electronic device.In vacuum environment,it converts electron kinetic energy into electromagnetic energy through the interaction between electron and electromagnetic wave.Finally,it realizes electromagnetic wave amplification.Terahertz（THz）TWT is a kind of TWT working in0.1THz-10THz.Compared with the semiconductor terahertz wave source,it has many advantages such as wide frequency band,low noise and high power.Its output power is even 4-5 orders of magnitude higher than that of solid-state devices.THz TWT is the"heart"to fill the"THz gap".It meets the requirements of THz communication,terahertz detection and other equipments.Slow wave structure（SWS）is the core part of TWT.All-metal SWS is an important branch of the SWS.It has many advantages such as good heat dissipation,large power capacity,strong structure,easy processing and so on.At the same time,it is compatible with new micro fabrication technology to make the structure more accurate and smaller.It can also work in THz band.Therefore,all-metal SWS THz TWT has become an international research hotspot.The research work of this paper mainly includes the following aspects:（1）An 850 GHz band electron beam TWT is designed based on the staggered double vane（SDV）SWS.Firstly,the high-frequency characteristics of 850GHz SDV SWS are studied by HFSS,and the single period is determined.Then,a simple side pull-out input-output structure is designed.At 820-880GHz,S11 is less than-15d B.S2 1 is more than-0.5d B.S3 1 and S41 are less than-40d B.Finally,the simulation of beam wave interaction is carried out.Under the condition of voltage of 30KV and current of 0.12A,the gain of single segment structure is more than 14d B at844-851GHz.The electronic efficiency is 1.5%.At 850GHz,the maximum output power is 5.3W.The corresponding gain is 16.28d B.The electronic efficiency is 1.6%.（2）A folded waveguide（FW）SWS TWT working in the same frequency band is also designed.The calculation results of transmission characteristics show that when the TWT works at 800-900GHz,S1 1 is less than-15d B,S2 1 is more than-0.5Db.S31 and S41 are less than-60d B.The calculation results of beam wave interaction show that when current is about 0.02A,the gain of single segment structure is more than 14d B at857-864GHz.The electronic efficiency is about 1.5%.At 860GHz,the maximum output power is 0.86W.The gain is 16.3d B.The electronic efficiency is 1.6%.（3）The electronic optical system which meets the different TWTs is also designed respectively.According to the traditional axially symmetrical pierce electron gun,sheet electron beam（SEB）gun and circular electron beam（CE）gun are designed and modified by CST.Finally,a permanent uniform magnetic field focusing system is designed for electron beam focusing.（4）The technology of THz diamond window is studied relatively.The processes mainly include the design of the window by CST,the analysis of various processes in the metallization process,and reliability experiment of the window.Finally,the results meet the requirements. |
PDF Full Text Request