准光腔回旋行波放大器三维数值模拟研究

发布时间：2019-02-20 09:42

【摘要】：毫米波波段的波长在1mm~10mm之间,工作频率在30GHz~300GHz之间。因为其频率介于微波和红外之间,所以其最大的特点是波长短和频带宽。回旋行波放大器是一种基于电子回旋脉塞效应的高功率微波器件,由于其具有大功率、宽频带的输出特点,近几年对于此种器件的研究越来越热。当随着器件的工作频率升高时,器件的尺寸共度效应和功率容量问题严重制约其发展的速度。解决此问题的常规手段是采用高次模式作为腔体中的工作模式,不过这又带来了模式竞争的问题。在毫米波波段因为器件的结构更小,这样模式竞争的问题就会更加激烈。由此而知,研究一种在毫米波波段具有模式选择性的互作用腔体成为了重中之重。准光腔是一种侧壁完全开放的结构,侧壁的开放使得一些模式从侧壁衍射出去,这种特性使得它具有模式选择性,能够很好的解决模式竞争带来的影响。本文研究的是以准光腔作为互作用腔体的回旋行波放大器件,研究准光腔对竞争模式的抑制成为重点。主要的工作如下:1、研究制约回旋行波放大器发展的原因。对准光腔结构进行分析及理论的研究。深入研究腔体中的高斯波束,并通过推导方程得到腔体中电磁场的分布表达式。分析准光腔对于电磁场的衍射损耗问题,通过对比圆波导和准光腔中的色散曲线的密度来确定该结构确实能对模式进行选择。为抑制竞争模式带来的影响奠定基础。2、对回旋管动力学理论进行分析,通过推导得到色散曲线方程。研究截断结构对于返波振荡的抑制。以准光腔为互作用腔体设计工作频率在140GHz的放大器,建立三维模型进行数值模拟。通过仿真数据分析截断结构对放大器稳定工作的影响。抑制返波振荡,优化结构参数与电参数,得到带宽为3.5GHz,峰值功率为820W的放大信号的输出。3、设计210GHz左右的回旋行波放大器,建立三维模型对其进行初步的探索。仿真得到峰值为320W的功率输出,并有1.0GHz的带宽。
[Abstract]:The wavelength of millimeter wave band is between 1mm~10mm and the operating frequency is between 30GHz~300GHz. Because its frequency is between microwave and infrared, its biggest characteristic is wavelength short and frequency bandwidth. Cyclotron traveling wave amplifier is a kind of high power microwave device based on electron cyclotron maser effect. Due to its high power and wide band output characteristics, the research on this device has become more and more popular in recent years. With the increase of the operating frequency of the device, the development speed of the device is seriously restricted by the problem of the dimension pass effect and the power capacity. The conventional way to solve this problem is to adopt the higher order mode as the working mode in the cavity, but this brings about the problem of pattern competition. In the millimeter wave band, because the device's structure is smaller, the mode competition becomes more intense. Therefore, it is very important to study a kind of interaction cavity with mode selectivity in millimeter wave band. The quasi-optical cavity is a completely open side wall structure. The opening of the side wall makes some patterns diffracted from the side wall, which makes it mode selective and can solve the influence of mode competition. In this paper, a cyclotron traveling wave amplifier with quasi-optical cavity as the interaction cavity is studied. The emphasis is on the suppression of competition mode by quasi-optical cavity. The main work is as follows: 1. The reasons that restrict the development of gyrotron traveling wave amplifier are studied. The optical cavity structure is analyzed and studied theoretically. The Gao Si beam in the cavity is studied in depth, and the distribution expression of the electromagnetic field in the cavity is obtained by deducing the equation. The diffraction loss of quasi-optical cavity to electromagnetic field is analyzed. By comparing the density of dispersion curve in circular waveguide and quasi-optical cavity, it is determined that the structure can select the mode. In order to restrain the influence of competition mode, the theory of gyrotron dynamics is analyzed, and the dispersion curve equation is derived. The suppression of back wave oscillation by truncated structure is studied. Using quasi-optical cavity as the interaction cavity, the amplifier with working frequency in 140GHz is designed, and a three-dimensional model is established for numerical simulation. The influence of truncation structure on the stability of amplifier is analyzed by simulation data. The output of amplifying signal with bandwidth of 3.5 GHz and peak power of 820W is obtained by suppressing backward wave oscillation and optimizing structural and electrical parameters. 3. A cyclotron traveling wave amplifier about 210GHz is designed, and a three dimensional model is established to explore it. The power output with a peak value of 320W and bandwidth of 1.0GHz is obtained by simulation.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN722

【共引文献】