| The millimeter wave frequency band is of great significance to the fields of information transmission and detection.Millimeter wave is also one of the key frequency bands for 5G communication.The development of millimeter-wave imaging,wireless communications and other technologies has created a huge demand for broadband and high-power millimeter-wave sources,and millimeter-wave vacuum electronic technique is an important way to achieve this goal.The millimeter-wave sheet beam traveling wave tube has a very wide operating bandwidth.At the same time,the sheet electron beam can effectively expand the current carried by it,thereby increasing the output power,which is an excellent choice to achieve wide frequency bands along with high power output.However,due to the theory of the beam-wave interaction in the traveling wave tubes,the phase velocity of the electron beam and the electromagnetic wave are required to keep in sync.As the electron loses kinetic energy in the interaction with the microwave,the velocity of the electron will gradually be slower than the phase velocity of the traveling wave and thus synchronize conditions have been disrupted,causing the beam-wave interaction unable to continue.This problem results in a generally low interaction efficiency,which greatly limits the device's ability to output high-power microwaves.In view of this,this article focuses on the method of improving the amplification performance of the device by achieving efficient beam-wave interaction in a sheet beam traveling-wave tube.The main contents of this article are as follows:1.The characteristics of the staggered double vane slow-wave structure are studied,and the effect of these characteristics on the beam-wave interaction in a sheet beam traveling wave tube is analyzed;2.Based on the large-signal theory of traveling wave tube and the characteristics of sheet beam TWT,a set of one-dimensional non-linear theoretical programs for calculating the beam-wave interaction of traveling wave tube using a numerical method is developed.This program is used to analyze the process of beam-wave interaction of traveling wave tube and obtain efficiency and output power results;3.The non-linear theoretical program and intelligent optimization algorithm are used to optimize the full-cycle phase velocity gradient structure to improve the interaction efficiency of the sheet beam traveling wave tube;4.The three-dimensional simulation software CST was used to calculate the interaction efficiency of the sheet beam traveling wave tube,and the high-frequency structure of the traveling wave tube previously optimized by the program was verified.The calculation results show that the optimized design of the high-frequency structure has achieved a large efficiency improvement in both program calculation and simulation verification,these optimization and verification are made in Ka and Ku frequency bands according to the needs of the laboratory;5.Summary and prospect of the above work.In summary,the beam-wave interaction process of traveling wave tube is researched and the high-frequency structure of the sheet beam traveling-wave tube is optimized.According to the results,the output power and efficiency of the sheet beam traveling wave tube are greatly improved,which paves the way for the design of a board-band and power millimeter wave source. |
PDF Full Text Request