Study On Energy Transmission Coupler And Collector Of Broadband Helix Traveling Wave Tube

High-efficiency broadband millimeter-wave traveling wave tube is an important type of vacuum electronic device,which can be widely used in high-performance radar,communications and other fields.In order to improve the transmission efficiency and the efficiency of the whole tube,the research and design of the energy transmission coupler and collector system are two key research contents;For this type of device,the theoretical and experimental studies of the energy transmission coupler and collector of the Ka-band broadband helix traveling wave tube and the collector of the 6-18 GHz helix traveling wave tube are carried out in this paper.The following work progress has been made:1.Through the combination of theoretical design and simulation,a coaxial line energy transmission coupler is designed for the Ka-band helix traveling wave tube slowwave structure.The design results show that its reflection coefficient is less than-15 dB and the standing wave ratio is less than 1.3 in the frequency band of 26.5-40 GHz,which meets the design requirements.2.After the design process above mentioned,the coaxial couplers and windows of the Ka band helix TWT are fabricated.Various problems encountered in the experiment are analyzed and solved.The experimental results show that the standing wave ratio is below 2.1.Then the error analysis of this experiment was carried out to prepare for the next experiment.3.In order to improve the efficiency of the traveling wave tube,the collector was studied.The electron motion and energy state after the interaction are analyzed,which provides a reference for the design and voltage setting of the collector.With the help of large-signal simulation software ORION,a two-dimensional simulation model of a four depressed collector is designed.Its collecting efficiency is 87.9%.4.A miniaturized four depressed collector has been designed of the 6-18 GHz band.On the premise of ensuring that its efficiency is not affected,reduce the inner radius of the original collector by 1.8mm and shorten its length appropriately.In order to study the asymmetric structure of the target collector,the 3D simulation software CST is used.A set of algorithms is designed to convert the 2D electronic entry data into 3D.Through comprehensive comparison in the two software,both the feasibility of the algorithm and the miniaturized design are verified.Finally,a four depressed collector with a reduced inner radius of 1.8mm and a length of 7mm based on the target structure was obtained.In addition,compared with the target collector,the electron reflow,secondary electrons and efficiency are improved to some extent.In addition,the designed five depressed collector achieves a collector efficiency of 8.77% higher than the original four depressed collector,while the inner diameter and total length are still smaller than the original four depressed structure.