Desigh And Research On High Frequency Structure Of Gyro-TWT And Dual-Band Gyro-TWT

Gyrotron-traveling-wave-tube?gyro-TWT?,which is based on the principle of relativistic electron cyclotron maser?ECM?,usually employs an over-mode non-resonant fast wave circuit to generate a high power,broad waveband at the range of sub-millimeter/millimeter to Terahertz band.These capabilities make it an attractive RF-wave source for advanced resolution radar,high-speed communication systems,and plasmas heating,material processing and crop dehydration,etc.High Frequency Structure?HFS?is one of the key components of gyro-TWT.Beam-wave interaction and competition modes oscillations are mainly occured at the HFS.The performances of early gyro-TWTs experiments were severe limited by such oscillation problems due to the smooth waveguide employed.It led that the development of gyro-TWT was slower than other types of gyrotron for a long time.Through the efforts of the study for the starting mechanization of the competition modes,scientists have proposed many beam-wave interaction circuits to suppress the competition modes.The lossy loaded waveguide is one of these circuits with the fastest developing speed and a wide range of application.In addition,the gyro-TWT with lossy loaded waveguide has achived a very good performances in experimental.Supported by the foundation of 2013ZX01011001,this thesis analyzes the HFS of the W-band gyro-TWT,the researchs for it as bellows:1.Designing the HFS of the lossy loaded W-band gyro-TWT by both the small and large signal theory;2.Employing the field matching theory to study the features of dieletric material,and choosing the suitable dielectric parameters for the W-band gyro-TWT;3.Predicting the output performances and proving the stability of the circuit by self-consistent theory and PIC simulation;4.Cold tests of the HFS components and hot tests of the assembled device.Comparing the results between theory and hot test,and putting forward some methods to improve the performances of the device after careful analysis.Although gyro-TWT has achied a great achievement and application in recent years,the traditional gyro-TWT does not satisfy the advanced resoluation radar,which can work at a large bandwidth,enven multi-bandwidth.Therefore,this thesis also focuses on the research of the novel dual-band gyro-TWT in the following fields:1.The feasibility study for the dual-band dual-mode gyro-TWT,and the study shows it can be realized by employing TE₁₁/TE₀₁ modes;2.Researching the key componets,such as MIG,HFS and output widow,etc.,in both theory and PIC simulation.Gyrotron oscillator is antother important type of gyrotron,which was verified the unique equipment for ITER heating so far.Because the gyrotron has a very stable output performance,therefore,it has a great application for material processing in industrial.Supported by the KIT foundation,this thesis also concentrates on the cavity design of 28 GHz second harmonic Continue-Wave gyrotron,the works for this gyrotron as follows:1.Designing the cavity for the 28 GHz second harmonic,TE₁₂ mode gyrotron,and using a smooth waveguide instead of straight waveigude as its interaction cavity;2.Studying the main competition modes,and put forward some methods to suppress the potential competition modes;3.Employing EURIDICE developed by KIT to study the performances of the 28 GHz gyrotron,and validated by the MAGIC 3D-PIC simulation...