Study On Novel Lfte-handed Metamaterial Structure Design And Application

With the birth of the frist left-handed metamaterial (LHM) realized by smith, the hypothetical medium has become a practicality. The LHM quickly becomes a hot topic of physics and electromagnetic research, because of its abnormal properties such as "negative refraction","backward wave "and so on.The main research work on LHM includes the following aspects:the electromagnetic properties of the LHM, the realization of the LHM, the experimental verification of the LHM, and the application of LHM. The realization and application of the LHM are studied in this paper. Firstly, the essential principle for the left-handed properties of the LHM is deeply investigated, making use of electromagnetic theory and circuit theory methods.On this basis, a new high performance LHM unit is designed.Then, the transmission characteristics of waveguide filled with LHMs, the design technology of microwave resonance structures dependent on LHMs, and the application of LHMs in high directivity antenna are deeply discussed in this paper.The major work and innovations in the dissertation are as bellows:1. The theory of designing and analyzing of the actual LHM structures is explained in detail by using of equivalent circuit method. The structures embrace continuous metal rod structure, cut wires structure, split ring resonators structure and simple short wire pair structure and so on.2. A new2D left-handed material unit is proposed by setting two reverse symmetrical Z metal strips on each side of the dielectric substrate respectively. The structure can present left-handed properties in X waveband, either electromagnetic waves incident perpendicularly or parallel to the plane of the substrate. By means of theoretical analysis, numerical simulation, extraction of the effective permittivity and permeability from S parameters, the left-handed properties are further analyzed and verified. And comparing the double Z-shape unit with the traditional H-shape unit shows that the double Z-shape Left-Handed structural unit is superior to the traditional H-shape structure, namely, the double Z-shape can redound to designing left-handed structural unit for double dimension incidence of electromagnetic waves.3. A Split Ring similar to Chinese character "Gong" LHM unit and a criss-cross structural unit are presented. These LHMs composed of thess structures only set on one side of the dielectric media, which can induce both negative permeability and permittivity and realize the left-handed properties.4. The transmission influence of the constitutive parameters on a rectangular waveguide working on TE10mode is analized. A novel resonance structure dependent on above designed LHM is presented and used to design and fabricate an improved miniaturized filter. The performance of the filter is confirmed by numerical simulations and experimental measurements, and the result shows that both the simulation results and measurement results are in good agreements. Two forms magnetic resonance structures of antenna covers are designed, which are the SRR structure working on TE wave mode and the short wire pair structure working on TM wave mode.The numerical simulation are made and the results are accorded with the theoretical analysis results. The high directivity patch antennas with high gain are also designed in this dissertation.