Research On High Power Helix TWT Within The Range Of 8GHz To 18GHz

Owing to the advantages of wide bandwidth,high power and high gain,the helix traveling wave tube(TWT)has become one of the most important vacuum devices.It has been used widely in communication,radar,electronic countermeasures and other fields.With the rapid development of the military electronic technology,it is essential that the helix TWTs have wider bandwidth,higher power,longer service life.Therefore,the high frequency system,the energy input and output structure and the steady-state thermal of the 8-18 GHz high power helix TWT have been studied in this paper.The main work of the paper is shown as follows:1.The dimension of the slow wave structure(SWS)has been determined.After studying a lot of different kind of SWSs,the SWS of the T-shaped rod and the T-shaped wing was selected as the research model.Next,the high frequency characteristics of the SWS has been simulated in order to satisfy the design requirements.After analyzing the effect of the different parameters in high frequency characteristics,the proper parameters have been determined.2.The beam-wave interaction of the helix SWS has been simulated.In order to suppress the backward wave oscillation and get a TWT of high output power,a helix structure with gradually varying pitch and diameter has been studied.The parameters of this structure are also determined.At the operating voltage of 16 kV and the operating current of 2A,the proposed TWT can generate 5200 W of output power over the frequency ranging of 8-18 GHz.3.The input/output structure of the SWS has been designed.The coaxial impedance conversion section and the window have been designed.In order to satisfy the requirement of high power output,the mode conversion and the window of the double ridge waveguide have been studied.4.The thermomechanical and electromagnetic characteristics of the helix TWT have been analyzed.The thermal analysis of the SWS not loaded heat sinks has been simulated by ANSYS.After calculating the heat source,the distribution of the temperature and deformation caused by the thermal stress have been simulated.The thermal analysis of the SWS loaded heat sinks has been analyzed in the same way.It can be seen clearly that the helix near the window has the highest temperature.By increasing the number of the heat sinks and adjusting the position of them,the SWS can work fine.This helix TWT can generate above 5200 W of output power over the frequency range of 8-18 GHz.Due to the ultra-wide bandwidth and the high output power,the proposed helix TWT can be used in modern electromagnetic applications.