Simulation Of Smith-purcell Superradiation Driven By Two Electron Beams

Terahertz(THz)wave is a waveband between microwaves and light waves.It is an electromagnetic wave whose frequency is from 100 GHz to 10 THz and its wavelength is from 30 ?m to 3 mm,Terahertz is in a very special area on the spectrum and has many unique properties.It is a hot topic of research.The terahertz source is the most important part of terahertz technology development.The vacuum electron source is an important radiation source.Its development is limited by the scale effect and the start-up current.Since the start-up current density is proportional to the square of the frequency,it is difficult to achieve this start-up current when advancing to terahertz.In response to this problem,this paper studies the dispersion characteristics and coupling characteristics of several subwavelength structures.The theoretical derivation and numerical calculations are used to analyze the effects of these structures on the reduction of the start-up current.These work have contributed to the development of terahertz technology.Progress has a certain positive significance.The following words are some specific contents of this thesis:(1)Derivation of multi-electron-beam coupled terahertz slow-wave structure dispersion equation.According to Maxwell's equations and boundary conditions,in the several regions of the slow-wave structure,the longitudinal component method is used to obtain the electric field components and magnetic field components in each direction by using the Holmholtz equation and the Floquet theorem in each region.After the field equations,the boundary conditions are used to match and eliminate the variables,so as to obtain the final dispersion equation.After the field equation is obtained,the boundary conditions are matched,all the variables in the equation group are eliminated,and finally,the dispersion equation can be obtained.(2)Coupling Characteristics of Multi-electron Slow Wave StructuresAfter obtaining the dispersive equation of the slow-wave structure,through the introduction of electron-injection related parameters,using MATLAB to draw the graph of the growth rate,observe the role of multi-electron beam structure in reducing the starting current,and analyze and compare the parameters of the starting current Impact.