| Millimeter wave source is the most important component of the millimeter wave system, it determines the performance of millimeter-wave system. Therefore, the development of millimeter-wave source that has stable performance and can output high power millimeter wave effectively becomes extremely important. At present the relatively mature high-power millimeter-wave source is cyclotron amplifier. The kyroklystron amplifier is the developed rapidly tube type of the cyclotron amplifier. Compares to Gyro-TWT amplifier, the kyroklystron amplifier has a large advantage in stability, output power and the efficiency of interaction. the kyroklystron amplifier have relatively low requirement of the velocity spread of electron beam that produced by electron gun, so it had won the attention of national research institutions and its development is the fastest in the cyclotron amplifier. However, because of the working principle and other reasons, the bandwidth of kyroklystron amplifier is relatively narrow, unable to meet the need for high power microwave source in future military and scientific research areas. Gyro-TWT amplifier becomes focus of national research at the present stage because of its relatively wide bandwidth. Countries have stepped up to the cyclotron traveling wave tube amplifier of the intensity, both in theory and practical application has made greater progress.In this thesis, the stability of the distributed dielectric loaded gyro-TWT amplifier have been analyzed, which from theory, numerical calculation and simulation.The main results are as follows:1. The self-oscillation of the gyro-TWT is investigated in detail. Using the small-signal dispersion equation and backward-wave linear gain to analyze the absolute instability. When attenuation exceed 3dB/cm, the absolute instability of the working mode TE0 1 is restrained.2: Designed the high-frequency structure of gyro-TWT with suitable dielectric loaded in accordance with the frequency, which can inspire the correct model TE01 model and effectively inhibited miscellaneous mode and self-excited oscillation.3: Programming the high-frequency structure of 35GHz continue-wave gyro-TWT in the particle simulation software Magic, find the best structure by an appropriating change about the structure ,the size and location of the dielectric-coated.The result shows an output power of 30.6kW with an electronic efficiency of 36.4% and a gain of 35.7 dB, a 2 GHz 3dB bandwidth is obtained with a 42kV,2A electron beam and a beam velocity of 1.46.4: The influence of the electronic beam parameters and high-frequency structure parameters on the output power, bandwidth, efficiency, and gain of the gyro-TWT are analyzed separately. and the results will provide the simulation reference for the further development of gyrotron amplifiers in the future. |
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