行波管噪声的研究

发布时间：2018-05-16 05:22

本文选题：螺旋线行波管 + 散粒噪声　；参考：《电子科技大学》2017年硕士论文

【摘要】：行波管和速调管是两种主要的线性注微波器件。其中,行波管是一种功率通常为几十到几千瓦,频带宽度可以到2个倍频程的宽带器件。而且,行波管具有非常广泛的应用领域,现今大多数卫星通信系统都使用行波管作为末级放大器。在大多数雷达系统中,都通常使用一支或若干只行波管作为产生高频发射脉冲的大功率放大器。由于行波管中电子发射的随机性,电子总是先后随机、速度不均匀地进入高频互作用区。这就意味着会不可避免地产生噪声,并导致通讯电子系统的输出功率变化,最终影响雷达系统的辨错能力和提高通讯系统的错码率。该文章采用理论分析推导与计算机宏粒子模拟的方法,深入研究了行波管噪声的产生、变化情况及抑制噪声的方法,论文的主要内容与创新点如下:1.研究分析了行波管噪声的产生、传播、增长及对功率的影响,这对解释行波管中噪声的形成机理有重要的意义。采用一维线性模型,并利用已有的行波管数据计算噪声系数随着距离的变化情况,并研究不同参数对噪声系数的影响。2.根据非线性宏粒子模拟的要求,设置噪声的初始状态。分别应用了SASE的自由电子激光宏粒子设置方式和麦克斯韦速度分布律来设置初始噪声,并且采用了伪随机数的方式对宏粒子随机化设置。应用噪声设置方案编写程序,结合行波管标准方程进行一维非线性噪声计算,并获得噪声功率谱密度。3.为计算行波管二维噪声,设计了26-40GHz和33-40GHz两只不同频段的螺旋线行波管的高频结构。利用HFSS软件与TAU软件配合使用,使得工作频段为33-37GHz输出功率在100w以上,37-40GHz在80W以上。26-40GHz行波管为追求最大功率,全频段输出功率都在200W以上。4.根据所设计的螺旋线行波管数据,开发了2.5维螺旋线行波管噪声计算程序,使其能够计算实际行波管的散粒噪声和速度噪声的功率谱密度。并且利用该程序探究不同电参数对噪声结果的影响,从而给出降低噪声的方法。
[Abstract]:Traveling wave tube and klystron are two main linear beam microwave devices. Among them, TWT is a kind of wideband device with power of dozens to several kilowatts and bandwidth of up to 2 times. Moreover, TWT has a wide range of applications. Nowadays, most satellite communication systems use TWT as the final amplifier. In most radar systems, one or more traveling wave tubes are usually used as high power amplifiers to generate high frequency transmitting pulses. Because of the randomness of electron emission in traveling wave tube, electrons always enter the high frequency interaction region at random and inhomogeneously. This means that the noise will inevitably be produced and the output power of the communication electronic system will change, which will ultimately affect the error-detection ability of the radar system and improve the code error rate of the communication system. In this paper, theoretical analysis and computer macro particle simulation are used to study the generation, variation and suppression of TWT noise. The main contents and innovations of this paper are as follows: 1. The generation, propagation, growth and influence on power of TWT noise are studied and analyzed, which is of great significance to explain the formation mechanism of TWT noise. Using one dimensional linear model and using existing TWT data, the variation of noise coefficient with distance is calculated, and the influence of different parameters on noise coefficient is studied. According to the requirement of nonlinear macro particle simulation, the initial state of noise is set. SASE's free electron laser macro particle setting method and Maxwell velocity distribution law are applied to set the initial noise, and the pseudo random number is used to set the macro particle randomization. In this paper, the noise setting scheme is used to write a program and the standard equation of traveling wave tube is used to calculate the one-dimensional nonlinear noise, and the noise power spectral density of .3is obtained. In order to calculate the two-dimensional noise of TWT, the high-frequency structures of two helical TWT with different frequency bands 26-40GHz and 33-40GHz are designed. Using HFSS software and TAU software, the maximum output power of 33-37GHz is over 100W, 37-40GHz, 80W, 26-40GHz, and the output power of all frequency band is more than 200W, .4. Based on the designed spiral TWT data, a 2.5 D spiral TWT noise calculation program is developed to calculate the power spectral density of the actual TWT's shot noise and velocity noise. The influence of different electrical parameters on the noise results is explored by using the program, and the method of noise reduction is given.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN124

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