Study On High Frequency System Of Millimeter Wave Dual-Band Space TWT

Dual-band TWT is one of special vacuum electronic devices which can make a slow wave circuit working at two frequencies band. The operating bandwidth of this kind of TWT need to be as wide as possible and the output power need to be as high as possible. It has great significance in the development of military strategy, and can not only make our radar and communications equipment lighter, smaller and more flexible, the more important is that it can also effectively avoid the interference of enemy.For the moment,about the research of dual-band space TWT which can make a slow wave circuit working at two frequencies band is just limited to some of the traveling wave tube research institute abroad, but research in this area is blank at home. This paper is about a kind of slow-wave structure of dual-band TWT working at Ka/Q band(29GHz~31GH and 43.5GHz~45.5GHz). In this paper,the feasibility of high frequency structure for dual-band TWT is analyzed,and the structure parameters are designed by simulation software,then the various work parameters are computed from the results of the simulation beam-wave interaction. It is shown that the designed dual-band space TWT helix has good index, and it can meet the design requirements well.It is significant that the research of this paper can provide a reference for the development and exploration of dual-band traveling wave tube. The main content of this paper are listed as follows:1. High frequency characteristics of slow-wave structure which is suitable for dual-band TWT is analyzed by using the three dimensional electromagnetic simulation software, and find out the influences between the high frequency characteristics and slow-wave structure.2. The coaxial line input and output structure for Ka/Q dual-band TWT are designed and optimized by CST software.3. The structure parameters and working parameters are designed by ORION software. According to these parameters, a 3D model of the Ka/Q double-band helix TWT can be established by CST software to simulate the PIC(Particle In Cell). Simulation results shows that the new Ka/Q dual-band helix TWT in Ka band which ranges from 29 GHz to 31 GHz can produce over 238.8W output power, gain is over 43.96 dB and conversion efficiency can reach over 12.76%, in Q band which ranges from 43.5 GHz to 45.5 GHz, the output power can reach over 243.9W, gain is over 43.86 dB and conversion efficiency is over 12.92%.