在模式耦合理论的基础上,采用传统的波导轴线常弯曲和改进的波导轴线正弦弯曲方法,对TE01-TM11模式变换器的几何结构进行优化分析,得到了最优几何参量. 以波导轴线正弦弯曲结构设计的8mm高功率圆波导TE01-TM11模式变换器的转换效率达到99%,带宽超过32%.同时还研究了蛇形线圆波导TE01-TE11模式变换器.

A self-consistent nonlinear theoretical model for a complex cavity gyrotron with abrupt transitions is presented in this paper. The model accounts for mode conversion in the transition region of the complex cavity through the general theory of modal expansion techniques. The interaction between the electron beam and TE61/TE62 RF field in the step cavity for a third-harmonic gyrotron is simulated; many calculations are carried out under different electron beam parameters.

A systematic theoretical and experimental study on 35 GHz 45KV third-harmonic gyrotron with a permanent magnet system is presented in this paper. A complex cavity with gradual transition, and a diode magnetron injection electron gun (MIG) are employed in the gyrotron. A self-consistent field nonlinear theoretical investigation and numerical simulation for electron beam interaction with RF fields are given. The diode MIG is simulated numerically utilizing our code in detail. The permanent magnet system provided the axial magnetic field of about 4.5KGs in the cavity region of the gyrotron. The Ka band third-harmonic complex cavity gyrotron with a permanent magnet system has been designed, constructed and tested. A peak output power of 146.3KW was obtained at a beam voltage of 45KV with beam current of 32.2A, corresponding to an efficiency of 10.2%.

The PaPer presents the design of the two-stage depressed collector system for 35GHz gyrotron, taking into account the effect of secondary electrons. Employed a new 2.5-D computer-aided design codes named CHAELOPS, including the auto-gridding generator, the electromagnetic solver, the accurate particle trajectory tracer and the secondary electron emitter including true secondary and backscattered seondary electron models based on Monte-Carlo method. The codes take into account either the safety and the reliability. The user interface is very friendly and fiexible. The collector electrode potentials were optimized in order to maximize the efliciency of the collector system s and minimize the effect of the secondary electrons. The primary beams come from the beam-wave interaction simulation codes. When the potentials were-20kV and -35kV, the magnetic com press ratio was 5.38, the better collector efliciency was 60.0％ with all the secondary electrons landing on the same electrode. The normalized velocity distribution of one trajectory in phase-space was shown in the paper, indicated the theory of the energy conversion of the electrons in retarding electric field and adiabatic magnetic field. The results comparison between EGUN and CHAELOPS has been made and good agreements have been obtained.

研究了具有突变结构复合腔回旋管注2波互作用自洽非线性理论. 用场匹配方法处理了腔中的突变结构,从具有电子流源的普遍传输线方程出发,研究了腔中注2波互作用非线性理论,在腔直径渐变部分考虑了模式之间的耦合. 利用此非线性理论模型,对突变结构复合腔三次谐波回旋管中电子流与H511 —H521模式对的高频场互作用进行了详细数值模拟,得出了许多有价值的结果. 计算结果表明,在合适的腔体结构尺寸下,注波互作用效率可大于25%.