Simulation Of 8mm Carbon Nanotube Cold Cathode Traveling Wave Tube

Carbon nanotube(CNT)has unique advantages in field emission,and because of its low operating voltage and high stability,it can be used as electron emission materials of cold cathode device.Traveling wave tube(TWT)is an apparatus that can be used to amplify the power of microwave and millimeter wave.So in order to develop microwave device with CNT field emission cold cathode,the research of CNT cold cathode TWT has a realistic meaning and practice value.In this thesis,the sheet beam electron gun and slow wave system of staggered double vane for TWT were designed.The main work of this thesis are as follows:1.The electro-optical system has been researched.Based on the theory of field emission,the field emission model of CNT is set up,what's more,the electro-optical system were also designed and simulated.Its performance parameters were presented from the simulation results,such as the trace of electron beam,and so on.2.The slow wave system of staggered double vane were designed and simulated.On the basis of staggered double vane slow-wave structure,this thesis deeply analyzed its Characteristics of the field distribution,dispersion characteristics and interaction impedance,we also analyzed the influence on dispersion characteristics and interaction impedance for the change of the structural parameter.Finally,staggered double vane slow-wave structure for 8mm TWT was designed.3.The input and output structures for 8mm TWT has been researched.In consideration of staggered double vane slow-wave structure,the special corresponding transaction structure of input and output couplers are proposed for this high frequency system to get stable output of the TWT.4.8mm carbon nanotube cold cathode traveling wave tube was researched.Carbon nanotube cold cathode was used as radiation source in TWT device.The TWT worked in in frequency range of 8mm band is researched by CST simulation software.The simulation results show that TWT with CNTs cold cathode worked at 32 GHz,the maximum gain was up to 32 dB in the frequency from 30.8GHz to 36.8GHz,and the signal efficiency was up to about 13.6%.