Simulation Research On A TWT Based On Magnetic Injection CNT Cold Cathode Electron Gun

The electron emission source of the conventional microwave vacuum electronic device mostly uses a hot cathode as an electron emission material,but the hot cathode itself has a non-negligible defect.However,the field emission cold cathode has a great advantage over the hot cathode,for example,it can increase the response speed of the system,reduce the power consumption of the system and facilitate the miniaturization of the device manufacturing.Therefore,the research on field-emission cold cathode has attracted more and more attention of researchers,especially the appearance of carbon nanotubes.It has become possible for carbon nanotubes to replace traditional hot cathodes as a new generation of new electron emission source materials.The slow wave system is the key structure that the TWT can excite the microwave signal and amplify it.Therefore,it is of great research value and application prospect to apply the carbon nanotubes to the TWT to take advantage of the cold cathode.This paper is based on the above background and has carried on the simulation research to the nano-cold cathode electron gun traveling wave tube based on magnetron injection.The main work of this thesis is as follows:1.The advantages of field-emission cold cathodes and the application of carbon nanotubes cold-cathode materials in traveling wave tubes are introduced.At the same time,a brief description of the working principle of the TWTs and their slow-wave structures is also provided.2.On the basis of understanding the principle of magnetron-injected electron guns,the modeling and design of magnetron-injected nano cold cathode guns was started and simulated in CST simulation software.Finally,after constant optimization and debugging,To meet the requirements of the electronic note,through the post-processing of the calculation results,we can see that the lateral velocity and the vertical velocity of the electron beam are increasing and decreasing respectively,and finally the velocity ratio is stable at ?=1.3.The helix is used as a traveling-wave tube slow-wave system,and the dispersion characteristics and coupled impedance characteristics of the helical slow-wave structure are analyzed.The slow-wave system is cut off and a centralized attenuator is used tosuppress the self-excitation of the traveling-wave tube.Oscillation and simulation calculation of the transmission characteristics of the entire slow wave system.4.After completing the research on electron guns and slow-wave systems,the PIC particle simulation of magnetron-injected nano cold cathode electron gun traveling wave tubes was started.From the calculation results,it can be seen that the traveling wave tube can be stable during operation.Finally,we analyze the change of the corresponding output power by changing the ratio of the longitudinal velocity ratio of the electron beam and the electron beam with the other parameters unchanged.