Research Of Rectangular-ring Vertex Bar Slow-wave Structure TWT

Travelling-wave tube plays an important role in military electronic fields such as radar and satellite communication due to its high power and small size.The size of the slow-wave circuit of the millimeter band traveling wave tube becomes smaller due to the "compatibility",which brings great challenges to the machining of the equipment.In addition,compared with circular electron beams,strip electron beams can deliver the same current at a lower current density.Therefore,it has become an important development trend to seek new slow wave structures based on micro-machining technology and suitable for strip injection.Based on this idea,a rectangular ring vertex single-bar slow wave structure is proposed.Rectangular ring vertex single-bar slow-wave structure TWT has the comprehensive advantages of being compatible with micro-machining technology,convenient interaction with strip beam and high interaction impedance.In this paper,the computer simulation method is used to conduct in-depth research and analysis of rectangular ring vertex single-bar slow-wave structure TWT.The main work is as follows:1.Firstly,the Ka band square ring vertex single-bar slow wave TWT is designed by using electromagnetic simulation software.The results show that the square ring vertex single-bar slow wave structure can provide wider working bandwidth and higher output power than the ring bar slow wave structure.The maximum output power at 33.5GHz is 1176 w,the corresponding maximum gain is 40.7d B,and the maximum electronic efficiency is 31.9%.Compared with the ring bar slow wave structure TWT,the maximum output power is increased by at least 25.1%,and the square ring diagonal single rod slow wave structure also has a strong ability to suppress the back wave oscillation.2.In order to further improve the power,the rectangular ring vertex single-bar slow wave TWT with banded electron beam is studied.The results show that with the increase of aspect ratio,the backward wave oscillation will appear in the rectangular ring vertex single-bar slow wave structure TWT.Based on this,this paper adopts the method of arranging truncation and attenuator to suppress the back wave oscillation.After suppressing the back wave oscillation,the TWT can provide the maximum output power of 1400 W,the corresponding maximum gain is 41.5d B,and the maximum electronic efficiency is 38.2%.In the last section of this chapter,H-type substrate metal sheet is designed.The results show that H-type substrate metal sheet will further broaden the bandwidth,but lead to the reduction of coupling impedance.3.Based on the pitch jump technology,the rectangular ring vertex single-bar slow wave structure with banded electron beam is optimized.The design results show that the pitch jump technology can further improve the power and efficiency.Compared with the uniform pitch,the power of the single negative jump mode is increased by 22.3% in the range of 28 ? 36 GHz.Compared with the average pitch,the power of the negative positive and negative three-stage jump mode is increased by27% in the range of 28 ? 36 GHz,and the maximum output power of 1800 W can be obtained.The corresponding electronic efficiency is 49.2% and the corresponding gain is 42.55 d B.