宽带行波管返波振荡及谐波抑制研究

发布时间：2018-09-14 08:11

【摘要】：螺旋线行波管具有较高的输出功率、较宽的工作频带、较大的增益等优越的性能,普遍应用于雷达系统、信息通信以及电子对抗等现代化的电子装备中。在实际应用中,行波管各方面性能的优劣将直接影响装备的使用效果,其中管子稳定性和可靠性是极其重要的两项指标,在影响螺旋线结构行波管稳定性的诸多因素中,振荡是最主要的原因,振荡包括有信号反射的振荡、返向波的振荡以及?模振荡,这三者中返波振荡对宽带行波管稳定性的影响最为重要。除了行波管稳定性之外,由于行波管本身所具有的高频非线性特征,输出的信号中除了输入信号的频率以外还混杂着二次谐波、三次谐波等谐波信号,这些干扰信号将会严重影响基波输出能量,降低了行波管的增益,因此非常有必要对螺旋线行波管的返波振荡和谐波抑制进行研究。本文从带有内置衰减器的螺旋结构行波管的高频理论和一维非线性理论着手,研究了螺旋线结构行波管的高频结构参数变化和内置衰减器位置及衰减量对返波振荡的抑制作用,然后用二次谐波注入法对2-6GHz宽带行波管谐波抑制进行了探讨,本文的具体工作内容包含下面三个部分:一.以带衰减器的慢波高频特性理论为基础,研究行波管内置衰减器对返波振荡的影响规律,利用电子科技大学自主研发的微波管CAD软件MTSS对2-6GHz宽带行波管进行仿真模拟,从正向波和返向波两方面研究了慢波结构内置衰减器的位置及衰减量与返波起振长度的变化关系,研究结果对行波管互作用部分的结构设计具有积极意义。二.以一维非线性理论为基础,采用MTSS仿真建模2-6GHz宽带螺旋线行波管,以维持色散平坦曲线,减小返波耦合阻抗为目的,详细研究了慢波高频结构中螺旋线、夹持杆、翼片参数变化对返波耦合阻抗的影响规律,并且比较了不同结构对返波振荡的影响程度,从而对整个高频结构进行优化,通过改变高频结构来抑制返波振荡。三.重点研究了二次谐波注入法对2-6GHz宽带行波管输出性能的影响,仿真模拟了在谐波注入前后基波输出性能的变化情况,通过模拟得到了注入二次谐波的最佳相位和最佳功率,并初步得到了在谐波注入之后,基波和基波的二次谐波输出功率随着注入谐波的功率、相位的变化规律。
[Abstract]:The spiral TWT has the superior performance of high output power, wide operating frequency band and large gain, and is widely used in modern electronic equipment such as radar system, information communication and electronic countermeasures. Property and reliability are two very important indexes. Oscillation is the most important factor affecting the stability of spiral TWT. Oscillation includes the oscillation with signal reflection, the oscillation with backward wave and the? Mode oscillation. Among them, the influence of backward wave oscillation on the stability of broadband TWT is the most important. Qualitatively, due to the high-frequency nonlinear characteristics of TWT itself, the output signals are mixed with the second harmonic, third harmonic and other harmonic signals besides the frequency of the input signal. These interference signals will seriously affect the output energy of the fundamental wave and reduce the gain of the TWT, so it is very necessary for the spiral TWT. Based on the high-frequency theory and one-dimensional nonlinear theory of spiral TWT with built-in attenuator, this paper studies the high-frequency structural parameters variation of spiral TWT and the suppression effect of the position and attenuation of built-in attenuator on the back-wave oscillation. This paper discusses the harmonic suppression of 2-6GHz broadband TWT. The specific work of this paper includes the following three parts: 1. Based on the theory of slow-wave and high-frequency characteristics with attenuator, the influence of the built-in attenuator in TWT on the back-wave oscillation is studied. The microwave tube CAD software MTSS developed by University of Electronic Science and Technology is used for 2-6GHz width. The position and attenuation of the built-in attenuator in the slow wave structure and the relationship between the attenuation and the starting length of the return wave are studied. The results are of positive significance to the structure design of the interaction part of the traveling wave tube. 2. Based on the one-dimensional nonlinear theory, the MTSS simulation model of 2-6 GHz is established. In order to maintain the flat dispersion curve and reduce the backwave coupling impedance of broadband helix TWT, the influence of helix, gripper and fin parameters on the backwave coupling impedance in slow-wave high-frequency structure is studied in detail, and the influence of different structures on the backwave oscillation is compared, so the whole high-frequency structure is optimized. The influence of the second harmonic injection method on the output performance of 2-6GHz broadband TWT is studied. The change of the fundamental output performance before and after the harmonic injection is simulated. The optimal phase and power of the second harmonic injection are obtained through the simulation, and the harmonic injection is preliminarily obtained. After entering, the second harmonic output power of fundamental wave and fundamental wave changes with the power and phase of injected harmonic.
【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】：TN124

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