Structural Unit With The Performance Of The Left-handed Materials Research

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 left-handed material 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, the design, realization and of the microwave LHMs used in waveguide and that matched to free-space are experimentally investigated. The influences of structure parameter, electromagnetic parameter of material, interaction between units on the electromagnetic resonance of SRRs and the plasmon resonance of wires are experimentally and numerically studied. The original works and valuable results of this dissertation are as follows:1. LHMs consisting of a periodic array of interspaced copper hexagonal SRRs and rods are designed and fabricated by using a hexahedron model. The influences of the azimuthal gap , the radial gap on on the electromagnetic resonance of SRRs are experimentally and numerically studied.2. LHMs consisting of a periodic array of interspaced copper hexagonal SRRs and wires are designed and fabricated by shadow mask/etching technique. The influences of the length , the thickness, the width, the electromagnetic electromagnetic parameter of material on the resonance of one-dimensional wire-array are numerically studied. The influence of periodic on the resonance of Two-dimensional wire-arrays is also investigated.3. The influence of the electromagnetic parameter of material on the transmission of LHMs is studied experimentally. The experimental results show that the transmission peak shifts to lower regime with the permittivity, which is caused by the decrease of the SRRs resonance.4. LHMs based on gridding wire-array, matched to free-space, are designed and fabricated by shadow mask/etching technique. Compared with LHMs base on traditional wire-array, it is showed that LHMs based on gridding wire has a betterLH transmission peak.5. LHMs comprised of capacitively loaded strip (CLS) and SRRs are designed for free-space. The influence of the length of capacitor, the width of strip, the polarization of EM waves on the resonance of CLS are investigated numerically.6. Two cases of LHMs, one in which the SRRs and CLS are non-planar and one in which they are planar are designed and the interaction between SRRs and CLS is Considered. It is confirmed that the SRRs, in addition to their resonant magnetic response, exhibit a resonant electric response, which results in the lower effective plasma frequency of CLS. On the other hand, the resonance frequency of SRRs can be shifted to higher by the CLS, which is in-plane with SRRs. However, the resonance frequency would not change when they are off-plane.