Investigation On Novel Rectangular Ring Vertex Bar Slow Wave Structure

Traveling wave tubes are mainly used in the military field,and are also widely used in the civil field.Compared with solid-state amplifiers,its frequency bandwidth,large output power,high efficiency and long lifespan play a very important role in vacuum electronic devices.As the frequency increases,the size of the traveling wave tube becomes small,which brings greater difficulties to processing.Compared with the circular electron beam,the sheet electron beam has a smaller lateral size,lower space charge force,and higher efficiency,making it an ideal radiation source.Therefore,a new type of traveling wave tube slow-wave structure based on the micro-electro-mechanical systems(MEMS)and capable of interacting with sheet electron beams has become one of the significant development trends.According to this idea,based upon the circular cross-section slow-wave structure research,a novel type of slow wave structure is presented,that is,a rectangular ring vertex bar slow-wave structure.This new structure is systematically simulated through experimental simulations.The main topics of this thesis are as follows:1.Focusing on conventional ring-bar slow wave structure,the novel rectangular ring vertex bar slow wave structure is proposed.The slow-wave structure and energy coupling structure of the Ka-band novel rectangular ring vertex bar traveling wave tube are designed,and the beam-wave interaction three-dimensional model is established in the CST particle studio,and the output power at each frequency point is obtained.The results show that the instantaneous 3-d B bandwidth of the novel rectangular ring vertex bar traveling wave tube is 8GHz,which means that the peak output power is greater than 200W from 28GHz to 36GHz frequency band.At the same time,the peak power of the traveling wave tube at the 32GHz frequency point reached 384 watts,its gain is 35.84 d B,and the electronic efficiency is 27.23%.2.Analyzed and studied the influence of the structure size on the high frequency characteristics of the novel rectangular ring vertex bar slow-wave structure,and designed the input and output energy coupling structure.The simulation showed that in the 20-40GHz frequency band,S₁₁ is less than-20d B,and S₂₁ is greater than-2d B,which shows that the structure has better transmission characteristics and very little reflection.3.In the same size structure,the beam-wave interaction model of the square diagonal single-bar slow-wave structure and the square center single-bar slow-wave structure is proposed.The results show that the output power of the square diagonal single-bar is more than 150W from 57 to 62GHz.The corresponding gain and electronic efficiency are greater than 38.75d B and 14.37%respectively.At 61GHz,the square diagonal single-bar has the largest peak output power of 225W,which is about 84.4%higher than the square center single-bar traveling wave tube.