The Research Of W-band KW-class Pulse Power Traveling Wave Tube

Traveling wave tube is one of the most widely used devices in microwave vacuum electronic devices,which realizes signal amplification through distributed beam-wave interaction,and has outstanding capabilities such as high power,large bandwidth and high efficiency.When the user demands higher and higher operating frequency range,the desired output power is getting larger and larger,the HF and high-power vacuum electronic devices have also become the pursuit of the industry.The research on vacuum electronic devices working in the LF is relatively mature,and many tube types have been successfully applied in military and civilian fields.In the high frequency part of the millimeter wave,especially the W-band and above,the research on the vacuum electronic devices is relatively weak.Both the W-band and 220 GHz-band are on the "atmospheric window",with strong penetration,anti-interference,narrow beam and high resolution,and have a wide range of development space.Therefore,the research on high-power microwave vacuum electronic devices operating in the W-band and above frequency band has high use value and practical significance.In this paper,a W-band sheet-beam traveling wave tube(TWT)which output power can reach 1 kW is designed.The sheet-wave interaction is simulated and analyzed,and the tube is processed,assembled and tested.The main research contents are as follows:1.The three-slot-staggered-ladder coupled-cavity slow-wave structure(CC-SWS)is optimized and improved,and the influence of different structural parameters on the high-frequency characteristics is analyzed to determine the size of the W-band three-slot-staggered-ladder SWS.A step-graded transition waveguide matching the three-slot-staggered-ladder SWS is designed,and a well-matched box-shaped output window is designed to provide an output window for microwave.The high-frequency characteristics of three-slot-staggered-ladder SWS are analyzed and Optimized by HFSS and the results show that the voltage standing wave ratio of the whole tube is lower than 1.2 in the range of 91.3-100.6 GHz.2.The CST simulation software is used to simulate the sheet-wave interaction of the W-band three-slot-staggered-ladder TWT,and adjust the parameters to achieve the expected power gain and maximum bandwidth.Under ideal conditions the simulation results show that the output power is over 1kW from 93 GHz to 99 GHz.The maximum output power is 1260 W at 94.3 GHz and the electronic efficiency is 11.4%.3.The clamping molds are design to assemble and fix the components of the three-slot-staggered-ladder slow wave circuit.Using UG to engineer all parts of the entire tube,then the transmission characteristics are tested after high speed CNC mill processing and assembling.The test results show that VSWR is lower than 1.5 from 89.34 GHz to 99.612 GHz,which is basically according with the simulation results.The above indicating that the transmission characteristics of the whole tube are good and meet the design requirements.4.A novel helix-groove rectangular waveguide(HGRW)slow wave structure(SWS)operating at THz band has been presented.The high-frequency characteristics of HGRW-SWS at 0.22 THz are calculated and compared with the traditional double staggered grating waveguide(DSGW)SWS.It is found that the HGRW has obvious advantages such as easy processing,low working voltage and large broadband,which provides a reliable idea for the development of W-band TWT and the terahertz TWT.