【作者】 李素萍；

【导师】 王子华；

【作者基本信息】 上海大学 ， 电磁场与微波技术， 2009， 博士

【摘要】 左手材料（LHM）是近年来电磁学领域研究的热点问题,越来越引起研究者的广泛关注。LHM是一种介电常数和磁导率同时为负值的人工合成材料,具有一些奇异的电磁特性,当电磁波在这种材料中传输时,电磁波的电场矢量、磁场矢量与波矢构成左手关系,而在普通材料中三者构成右手关系。本文对覆盖层或衬底是左手材料的平板波导中的导引模做了深入研究,并详细讨论了不同结构平板波导中的表面模,发现了振荡模和表面模的一些新的特性。论文主要包括以下内容:首先,研究了覆盖层或衬底层是左手材料时,不对称平板波导中的导引模,引入归一化参数,用解析法得到其色散曲线,并分类详细讨论了振荡模和表面模的色散特性。TE₀振荡模有时不存在;有时仅在有限的归一化传播常数范围内存在。TE₁表面模的色散曲线与TE₀振荡模的曲线平滑连接,形成一个完整的曲线,有时存在二重简并现象。其次,用解析法分析了覆盖层或衬底是左手材料的不对称空心平板波导的TE表面模,求出了表面模的色散方程,画出了色散曲线,并详细讨论了波导的结构参数对其色散特性的重大影响。另外,对TM表面模的色散特性也做了说明。第三,用准光学的方法研究左手材料平板波导的表面模。引入一种射线模型,来研究平面迅衰波的传输特性。研究发现平面迅衰波在界面处反射和透射时会发生振幅跃变。还首次用射线图分析了含左手材料的单界面和平板波导中的TE表面模。我们发现,在芯层是LHM的平板波导中,结构参数对表面模的存在有很大的影响。在覆盖层或衬底是LHM的平板波导中,奇表面模不存在,但存在两种偶表面模。另外,对振荡模和表面模之间的导引机理和条件做了比较。第四,介绍了用于实现左手材料的重要组成单元一金属开口环谐振器（SRR）和互补开口环谐振器（CSRR）,研究了它们的结构特点及其微带滤波器。它们能够应用于微波滤波器的设计中,以减小滤波器的尺寸,优化滤波器的性能。最后,我们不光做了以上的理论研究,为了丰富博士论文,还做了毫米波段的实验测量。椭圆偏振测量法是一种高灵敏度、非接触的现代检测技术,在薄膜参数及其特性的测量方面有着广泛的应用。将椭偏法的电磁频谱从原来可见光、红外波段拓展到毫米波段,分析了毫米波椭偏法测量原理,使用已构建的实验装置进行测量,通过对测量结果的分析,选择了合适的入射角,并进行了大量的测试,从而计算出了样品的复介电常数。更多还原

【Abstract】 The study of the left-handed material （LHM） has been a hot topic in the electromagnetics for the past years, and attracts much more attention for scientists. LHM is a composite material with simultaneously negative dielectric permittivity and magnetic permeability, and possesses a number of remarkable properties. As electromagnetic wave propagates in this material, the electric field, magnetic field and wave vector form a left set of vectors. However, for conventional material, the three vectors form a right set of vectors. In this dissertation, a deeper study on the guided modes in slab waveguides with a left-handed material cover or substrate is presented, and the surface guided modes with respect to different parameters are researched in detail. In this way, we explore more new and unusual properties of oscillating and surface guided modes. The dissertation is summarized as follows:Firstly, the guided modes propagating along an asymmetrical dielectric slab waveguide with a left handed material cover or substrate are studied, respectively. By using normalized parameters, universal dispersion curves have been obtained analytically. Then the dispersion properties of oscillating and surface guided modes are classified systematically and discussed in detail. TE₀ oscillating mode some times does not exist; some times it exists in a restricted range of normalized propagation constant. The dispersion curve of TE₁ surface mode smoothly connects with that of TE₀ oscillating mode. It seems that the two different kinds of modes compensate each other to form one whole mode, and some times the whole mode curve is double degeneracy.Secondly, TE surface modes in asymmetrical hollow slab waveguide with a left handed material cover or substrate are investigated analytically, respectively. The dispersion relation is derived, and the dispersion curves are calculated. We find that the constitutive parameters have important effect on dispersion properties. In addition, TM surface modes also are discussed.Thirdly, we study the surface guided modes in a left-handed material slab waveguide using the method of quasi-optics. A ray model for an evanescent plane wave has been introduced to describe the property of propagation. It is found that an evanescent wave undergoes an amplitude jump during reflection and transmission on a plane interface. TE surface modes guided by a single interface and a slab waveguide containing left-handed materials are then analyzed by using a ray picture, respectively. We find that existence of surface modes in a LHM slab is strongly dependent on constitutive parameters. In a slab waveguide with left-handed material cover or substrate, odd surface mode does not exist, but there exist two even surface modes. Besides, guiding mechanics and conditions are compared between oscillating and surface guided modes.Fourthly, the split-ring resonator （SRR） and complementary split-ring resonator （CSRR） that act as fundamental composite units to make left-handed material are discussed. The constitutive characters and the planar microstrip filters that based on SRR and CSRR are researched. SRR and CSRR can be used in design of microwave filter in order to miniaturize the filter and improve its performances.Lastly, in order to make the dissertation better, we not only do the research above in theory, but also do an experiment in millimeter-wave band. Ellipsometry is a kind of famous measurement technology with the character of contactless and remarkable sensitivity, and it plays a very important part in measuring dielectric character of materials. The electromagnetic frequency band of ellipsometry is extended from visible light and infrared band to millimeter-wave band. We analyze the measurement principle of ellipsometry in millimeter-wave band, and do an experiment using the built measurement apparatus. According to the measured results, the appropriate incident angle is chosen. At last, we get the complex permittivity of materials basing on a lot of measured data.更多还原