【作者】 王兵；

【导师】 文光俊；

【作者基本信息】 电子科技大学 ， 通信与信息系统， 2015， 博士

【摘要】 具有高功率、宽频带和高效率的毫米波辐射源在高速通信、雷达以及电子对抗等领域都有广泛的应用。行波管作为一类重要的毫米波器件由于其具有高功率容量,宽频带等特点在毫米波辐射源中有着重要的应用。传统的螺旋线行波管虽然有着宽的带宽,但因其慢波结构具有相对较低的功率容量而限制了它的发展。不仅如此,随着频率的升高,螺旋线的加工也变得困难。最近几十年全金属慢波结构得到了广泛的发展,越来越多的学者对其展开了研究,这主要是因为全金属慢波结构具有尺寸大、热耗散能力强、整体性能好等优点,其中圆盘加载波导就是一种重要的全金属慢波结构。本文在圆盘加载波导的基础上,对同轴交错圆盘加载波导及其改进形式进行了研究,研究表明这类慢波结构在毫米波多注行波管中有着较好的发展前景。本论文主要是从高频特性、电磁波传输特性、注波互作用特性三个方面对同轴交错圆盘加载波导进行了深入的研究,并指出了可以将其应用于毫米波多电子注行波管的设计。论文的主要工作成果为:一、在考虑加载圆盘厚度的情况下,首次采用多导体传输线分析方法对同轴交错圆盘加载波导进行了理论分析,推导出了其色散方程。通过数值计算的方法对色散方程进行了求解,其计算结果与通过计算机电磁仿真得的结果一致。通过计算结果可以看出,选择合适的参数可以使慢波结构得到较宽的带宽。理论分析结果为后面的应用研究奠定了基础,并提供了有效的模型参数。二、对同轴交错圆盘加载波导的高频特性展开了研究,利用ANSOFT HFSS对同轴交错圆盘加载波导进行了建模分析,研究表明:同轴交错圆盘加载波导的内径ra和单位周期长度L对慢波结构高频特性的影响要大于其它的结构参数。减小内径ra可以显著提高慢波结构的耦合阻抗,减小单位周期长度L可以显著降低慢波结构相速。三、为了提高同轴交错圆盘加载波导的高频特性,提出了两类脊加载结构:圆盘边缘脊加载结构和圆盘中间脊加载结构。圆盘边缘脊加载结构可以显著降低慢波结构的相速,用作行波管时可以降低工作电压。从论文的研究可以看出在采用了边缘脊加载结构后,在耦合阻抗变化很小的情况下,慢波结构的归一化相速从0.29降到了0.24,下降了17.2%。圆盘中间脊加载结构在整个频带内可以明显提高同轴交错圆盘加载波导的耦合阻抗,用作行波管时可以提高注-波互作用的效率。同时,论文还对几种周期圆盘加载波导结构的高频特性进行了比较,研究表明,采用同轴交错圆盘加载方式不仅可以减弱色散,而且对降低慢波结构的相速也有积极的作用。四、提出了具有400W峰值功率水平的V波段八电子注同轴交错圆盘加载波导行波管的设计方案,并利用CST PIC-Solver软件建立了同轴交错圆盘加载波导的多电子注行波管三维注-波互作用物理模型,对其非线性互作用情况进行了模拟分析。研究结果表明:在所设计的输入输出结构下,慢波结构的反射系数S11小于-25d B。在11.2k V电压和120m A电流下,提出的设计在44.5GHz-46.5GHz的频带范围内具有30d B以上的增益,最大输出功率达到462W,电子效率达到了4.3%,最大增益达到31.1d B。因此,在研制毫米波多电子注行波管方面,同轴交错圆盘加载波导是一种具有发展潜力的慢波结构。综上,同轴交错圆盘加载波导是一种高频特性良好的全金属慢波结构,通过对这种慢波结构的研究将推动毫米波行波管的发展,尤其为大功率、多电子注行波管的研究提供了一种新的方向。更多还原

【Abstract】 Millimeter-wave radiation sources with high power, wide bandwidth and high efficincy are attractive for many applications, such as high-date-rate communication, radar and electromagnetic countermeasure. Due to its outstanding combined performances in power capacity and band width, the traveling wave tube plays important role in millimeter-wave radiation. The helix cuircuits, as a traditional slow wave structure has wide bandwidth, but its power capaplity is small. Meanwhile, as the working frequecy increases, the fabrication of helix circuit becomes difficult. Recently, the all-metal slow wave structures attract many scholar’s interest for their peculiarities:large size, high precession of manufcturing and assembling. Because of these advantages, the all-metal slow wave structures are widely used. The disk-loaded cylindrical waveguide is one of the most important slow wave structure in the all-metal slow-wave structures. In this dissertation, we have made detailed studies on the coaxial interlaced disk-loaded waveguide. The results show that it has important application merit in multi-beam millimeter-wave traveling wave tube.This dissertation does a detailed analysis for the coxial interlaced disk-loaded waveguide on three aspects, including high frequency characteristics, transmission characteristics and beam wave interaction characteristics. The reaserch shows that the coaxial interlaced disk-loaded waveguide can be applied as slow-wave structure for multi-beam millimeter wave traveling wave tube. The major achievements are listed as the followings:1. The dispersion equation of the coaxial interlaced disk-loaded waveguide slow-wave structure is derived by means of multi-conductor transmission line method under the condition of thinking the thickness of disk. Meanwhile the dispersion equation is solved by means of numerical computation method, and the results are agree with those from software simulation. The coaxial interlaced disk-loaded waveguide could get wide bandwidth when select proper structure parameter. The theoretical analysis is the foundation of the research, meanwhile it provide the valid model parameter for the application.2. It is analyzed that the change of structure parameter affects dispersion characteristic and interaction impedance of the coaxial interlaced disk-loaded waveguide using electromagnetic simulation software ANSOFT HFSS. The results of research show that the inner conductor radius ra and period length L have greater effects on high frequency characteristic than other structure parameters. Along with the decrease of ra, the interaction impedance increase obviously. The phase velocity can be decreased apparently by reducing the period length L.3. In order to improve the high frequency characteristic of the coaxial interlaced disk-loaded waveguide, two different ridge-loaded structures are proposed: edge-ridge-loaded structure and middle-ridge-loaded structure. The results of research show that the normalized phase velocity of the edge-ridge-loaded structure reduced apparently compared with that of the coxial interlaced disk-loaded waveguide, from 0.29 to 0.24, decreased 17.2%, however the coupling impedance changes slightly. The middle-ridge-loaded structure has great effect on interaction impedance, and the loaded ridge makes the interaction impedance increased noticeably. When these two ridge-loaded structures are used as slow wave structure of the traveling wave tube, the operating voltage can be decreased and the beam-wave interaction efficiency is improved respectively. At the same time, some other kinds of disk-loaded cylindrical waveguide are investigated. The results show that the coaxial interlace disk-loaded structure can not only get weak dispersion but also make more contributions on decreasing the phase velocity than other structures.4. We also proposed a design scheme of the V band eight beams coaxial interlaced disk loaded waveguide traveling wave tube with peak power of 400 W. Furthermore, the process of the nonlinear beam-wave interaction in coaxial interlaced disk loaded waveguide is simulated by CST PIC-Solver. The investigation reveals that the reflection parameter S11<-25 d B is achieved. The traveling wave tube has a gain over 30 d B in the frequency range of 44.5-46.5GHz, and the electronic efficincy is about 4.3%. The maximum peak power is 462 W and the maximal gain is 31.1 d B. Therefore, the coaxial interlaced disk-loaded waveguide has potential application in multi-beam millimeter wave traveling wave tube.In summary, the coaxial interlaced disk loaded waveguide is an all metal slow wave structure with excellent high frequecy characteristics. The investigation of this slow wave structure is important to the millimeter traveling wave tube, especially as a new slow wave structure for the high power multi-beam traveling wave tube.更多还原