Distributed Medium Load Cyclotron Research Of Traveling Wave Tube

The gyrotron was mainly applied in controlled thermonuclear fusion in the past long time, gyrotron can produce high average power, but it is a self-excited oscillator, rather than a phased amplifier. Owing to weight and volume, the gyrotron is not suitable for the popular radar systems. In order to meet the requirement of radar systems, a gyrotron amplifier is in need. A gyrotron traveling wave amplifier and a gyroklystron amplifier is the two main amplifiers, a gyroklystron amplifier operating in the low-loss TE01mode has produced an average power of kW at94GHz. However, the bandwidth limited by the Q of the cavities, was less than1percent. The gyrotron traveling wave amplifier can produce high average power, but also wide band, these advantages are in special need in radar systems like Doppler radar systems, etc. So the gyrotron traveling wave amplifier has gradually become a research focus in most countries.Has been subject to the complex interaction mechanisms and the parasitic mode competition, the development of the gyrotron traveling wave amplifier was relatively slow, until the late1970’s gyrotron traveling wave amplifier has got rapid development. Domestic research lagged in the gyrotron traveling wave amplifier. Relative research of Ka-band and V-band gyrotron traveling wave amplifier in High Power Microwave Laboratory of University of Electronic Science and Technology of China began relatively early, the output power and gain higher to meet the high power output requirement, but considered in terms of relative bandwidth, the bandwidth of W-band is better to meet the requirements of the broadband microwave source, so it is necessary for the W-band gyrotron traveling wave amplifier research.In this paper, Starting from the certain background of the gyrotron traveling wave amplifier, international research focus of the gyrotron traveling wave amplifier are two ways of distributed load and cycle load to complete the development of the amplifier. The research in this paper we adopted the way of distributed load to suppress the parasitic oscillation including the absolute instability and cyclotron backward wave oscillation. We began the linear theory firstly, through the linear theory of the gyrotron traveling wave amplifier study, We can not only understand the concept and significance of the absolute instability and cyclotron backward wave oscillation, but also found the way to suppress these two oscillation, in the same time, we can supply the initial value for the nonlinear simulation which can save time and labor. Owing to nonlinear simulation closer to the engineering practice, according to the requirements of the hot beam tube experiment,1study and discuss the influence on the spectrum of the tube, the input power, output power, gain and efficiency by the electron beam parameters, high-frequency structural parameters of the gyrotron traveling wave amplifier, also the transducer process between electron beam and wave.Finally, the magnetron injection gun for the gyrotron is studied, the PIC simulation results of the gun is given, and the PIC simulation experience is helpful to the gun for the gyrotron travelling wave amplifier.