| The gyrotron traveling-wave tube is a relativistic nonlinear vacuum electronic device,which has an irreplaceable advantage in microwave millimeter wave and terahertz band.It has the advantages of simple structure,high output power,high gain,high working frequency and wide bandwidth.It is suitable for high frequency and high energy field such as radar,communication,electronic warfare,plasma heating and so on.The interaction structure of the gyro-TWT is one of the core components of the gyro-TWT.It is the main place for the interaction between in electron beam and high frequency electromagnetic wave,and it is also the main place to realize the energy conversion between in electron beam and electromagnetic wave.However,due to its transverse interaction mechanism,high-frequency structure is sensltive to competitive mode oscillation,limiting the performance of cyclotron tube.Therefore,many researchers are devoted to the study of multi-mode oscillations of gyro-TWT.A variety of methods have been developed from theory and practice to suppress the multimode oscillations of gyro-TWT and improve the working performance of gyro-TWT.The use of dielectric-load in high frequency structures is a widely used,mature and effective method.In this paper,the theory and types of the multimode oscillations of the gyro-TWT are discussed.By combining the field equations of the circular waveguide multi-mode superposition and the equation of the cyclotron electron beam equations,the multi-mode interaction equations of the gyrotron traveling-wave tube are obtained.At the same time,the principle and influencing factors of a variety of self-excited oscillations in the gyrotron traveling-wave tube are analyzed,and the suppression method is considered.And the ant colony splitting algorithm suitable for the gyro-TWT is developed.The high frequency structure of the gyro-TWT is simulated and optimized by numerical optimization algorithm.A high-frequency structure of the distributed dielectric-load gyro-TWT is designed.The output power reaches 136.63 kW,the efficiency reaches 28.46%,the saturation gain reaches 51.36 dB,and the bandwidth reaches 7GHz.The main research work of this paper is as follows:1.Considering the multimode effect in the self-consistent nonlinear theory of the gyrotron traveling-wave tube,the electromagnetic wave distribution and the electron beam motion equation of the multi-mode interaction are analyzed,and the multi-mode interaction equations are obtained.2.The types of self-excited oscillations in the gyrotron traveling-wave tube are discussed,and the mechanism,influencing factors and suppression methods are analyzed.Talking about the reflection oscillations from the port reflection.3.Pointing at the gyrotron traveling-wave tube,the ant colony splitting algorithm is developed on the basis of the ant colony algorithm.Programing the program of optimization algorithm.The algorithm is used to optimize the interaction structure of the gyrotron traveling-wave tube.4.The simulation results of dielectric-load interaction structure of W-band with good performance are obtained by Particle-in-cell(PIC)particle simulation. |
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