Cyclotron Amplifier Simulation Studies

Because of the high energy density, anti-interference ability and high-resolution, the high-power millimeter-wave has an important application in high-power millimeter- wave radar, communications, electronic countermeasures, precision-guided , controlled thermonuclear fusion and many other fields. Be restricted by various factors, such as structure, process materials and the mechanism, the conventional vacuum electron devices is not suitable for working at the millimeter-band. The gyro-device based on the principle of electron gyro-resonance has become the main choice for the millimeter- band high-power microwave radiation because of the use of the smooth waveguide and so greatly reduces the complexity of the structure. However, because the mechanism of interaction is rather complicated, very susceptible to parasitic interference mode, the Gyro-TWT amplifier develops slower than the oscillation tube and gyroklystron. The interaction mechanism of Gyro-TWT and the structure design of the millimeter-wave gyrotron have been the hotspot and the difficulty in the research. In this paper, the main job is as follows:1. With the PIC software MAGIC we completed the program for the use of the design of 30GHz Gyro-TWT high-frequency structure, and designed a new structure with the loss ceramic loading for Ka-band Gyro-TWT, which greatly suppressed oscillations and improved the efficiency of the amplifier. For analysis the beam-wave interaction characters of Gyro-TWT amplifier, we tracked and simulated the process of the beam-wave interaction with the PIC simulation software MAGIC, and discussed the effect on the characters of output at different parameters.2. The simulation results show that our Ka-band Gyro-TWT amplifier with the loss dielectric loading structure achieved a output power about 340kW at 30GHz with an electron beam of 60kV and 15A, magnetic field B=1.107T with a beam-wave conversion efficiency exceeding 38%, gain above 44.6dB and 3dB bandwidth about 3.5GHz.3. The structure parameters and simulation results of the analysis were applied to the actual research and development, and participated in the cold test of the high-frequency structure, the entire tube assembly, welding, exhaust and hot tests on the sample tube. The test results are as follows: in the frequency of 29.5GHz, the maximum pulsed power 182kW, gain 32.7dB, interaction efficiency of 20.2%, 3dB bandwidth of 1.8GHz.4. Completed the program for the Ku-band Gyroklystron high frequency structure with the simulation software MAGIC. The results show: at 15GHZ, a output power of 604kW with an efficiency of about 43% and a gain of 35.7dB, and a 280MHz bandwidth is obtained with a 70kV,20A electron beam and a=1.45.