周期膜片加载椭圆波导的研究

【作者】 徐进；

【导师】 王文祥；

【作者基本信息】 电子科技大学 ， 物理电子学， 2006， 硕士

【摘要】 在各种微波器件如滤波器、辐射器、谐振器和宽带传输线中椭圆波导有着广泛的应用。周期加载波导在高功率微波管、波纹喇叭和线性加速器等中起着重要作用。全金属慢波结构因其尺寸大、热耗散能力强、整体性能好等优点被广泛应用于宽带、大功率行波管和相对论行波管中,而膜片加载慢波系统正是全金属结构中最重要、应用最广泛的一大类结构。而到目前为止,人们对椭圆截面的周期加载结构的关注还比较少。在本论文里,我们讨论了周期膜片加载椭圆波导作为慢波结构的射频特性,这种结构有可能应用于高功率器件和毫米波段的滤波网络。本论文的主要工作:由于在使用马丢函数时存在一些困难,主要是因为不能简单方便地对其进行解析表示,我们给出整数阶各类马丢函数的详细计算方法,该方法适合较大范围的阶数n和参数q值,实际计算中采用了Matlab软件进行编程实现,并给出了各类马丢函数在自变量和q值两个参数变化下的三维可视化图形。分析了周期膜片加载共焦椭圆波导,在考虑空间谐波和不考虑空间谐波两种情况下的慢波特性。应用场匹配方法得到这种结构的色散方程和平均耦合阻抗。研究了特征行列式阶数对计算精度的影响,通过数值分析讨论了不同离心率对色散和耦合阻抗的影响。发现椭圆短半轴长度保持不变,增加长半轴能减小色散,而耦合阻抗在高频段变化缓慢,有较大的值。采用场匹配法和椭圆柱波函数加法定理对具有圆中心孔的周期膜片加载椭圆波导进行了理论分析。分别推导得出这一结构的色散方程和平均耦合阻抗,并进行数值计算,计算结果与CST软件仿真能很好地吻合。研究了不同结构尺寸对慢波特性的影响。最后对该结构的模式隔离度进行了探讨。更多还原

【Abstract】 Elliptical waveguides have found wide applications in a variety of microwave components: waveguide filters, radiators, resonators, and wide-band transmission lines, etc. Periodic-loaded waveguides play very important roles in high-power microwave tubes, corrugated antennas and linear accelerators. Owing to having the advantages of large size, good thermal conductivity, high precision of manufacturing and assembling, the all-metal slow-wave structures are widely used in the wide-band, high power Traveling Wave Tube (TWT) and relativistic TWT. Furthermore, the disc-loaded cylindrical waveguide is one of the most important slow-wave structures in the all-metal slow-wave structures (SWS). Periodic structures involving elliptical section have received limited attention thus far. In the dissertation, The RF characteristics of the periodically iris-loaded elliptical waveguide used in slow-wave structure is discussed. The structure has potential applications to high-power microwave devices and filtering networks at millimeter wave frequencies. The major achievements are listed as the followings:Mathieu functions remain difficult to employ, mainly because of the impossibility of analytically representing them in a simple and handy way. The methods for the computation of all Mathieu functions of integer orders for large range of the order n and the parameter q were presented here. The calculations were made by programs using Matlab to compute the Mathieu functions. The visualization of Mathieu functions was presented by three-dimensional surface.The slow-wave characteristics neglecting and taking account of space harmonics (SH) for periodically iris-loaded confocal elliptical waveguides are analysed, and the dispersion equation and the mean coupling impedance of this structure are obtained by更多还原