Dissymmetrical Hexagonal Split Ring And The Electromagnetic Characteristics Of The Dendritic Microwave Left-handed Materials

Left-handed metamaterials (LHMs) are characterized by a negative effective permittivity and simultaneously a negative effective permeability, and present a variety of unusual electromagnetic and optical properties, such as reversed Doppler shift, Cherenkov radiation, Goos-Hanchen shift, negative refraction effect and perfect lens, etc. The discovery of LHMs has been regarded as one of the ten most significant discoveries in science community in 2003, and has been the front and focus area in physics and electromagnetics research. In this dissertation, single dissymmetrical hexagonal split ring resonators (SRRs) and multilevel dendritic geometry are designed. The influences of structure parameter, electromagnetic parameter of material, interaction between units on the electromagnetic resonance are experimentally and numerically studied. The original works and valuable results of this dissertation are as follows:1. Inspired by the dendritic geometry in nature, we the single dissymmetrical hexagonal split ring resonators (SRRs). The SRRs were fabricated on one side of dielectric substrate using shadow mask/etching technique. By experiments and computer simulations, we have researched on the microwave transmission behavior of the SRRs at frequence band between 8-12GHz. The results show that, for an individual hexagonal SRR, the resonance frequency is affected by the size of the SRR; for two SRRs, there are two resonance peaks in the transmittion curve when they are closed to each other for three SRRs or the radialized rings, the resonance frequency of the structure with high level branches shifts towards lower values comparing to that with no branches. The simulations is in agreement with the experiments results.2. We study the transmission property of the multilevel dendritic geometry. The geometry produce an electrical resonance and more than one magnetic resonances. By changing the length of dendritic geometry, we can tune the magnetic resonance into the negative permittivity band and achieve a LH transmission regime using only the dendritic geometry. The 3-order dendritic structures are fabricated on one side of dielectric substrate using shadow mask/etching technique, and get LH behavior at frequence band between 8-12GHz in experiment. We measure the transmission phase of 3-order dendritic structure and find that it has a boundance at LH frequency band.3. S-parameter retrieval method is suggested to calculate refractive permeability, permittivity, index of LHMs, using CST software to calculate S parameter, and using...