The Propagation Of Electromagnetic Wave In Slab Waveguides With A Left-handed Material

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.