The Design And Characteristics Of Left-handed Materials Structure Design

Left-handed metamaterial (LHM) is a artificial electromagnetic material in which both the permittivity and permeability are simultaneously negative, perform extraordinary electromagnetic properties, such as reversed Doppler shift, reversed Cherenkov radiation, reversed Goos-Hanchen shift, negative refraction and perfect lens. The discovery of left-handed material has been regarded as one of the ten most significant discoveries in Science community in 2003. It was Materials Today's top 10 advances in material science over the past 50 years and was the front and focus area in physics and electromagnetic research.Now the research of LHM is focus on the constructional design and application . The constructional design is fundament of all. When the first Split ring resonators(SRRs) which show negative refraction in 4.2GHz～4.6GHz was studied, some new constructional designs were found, such as high dielectric resonators, semi-conductor, and surface plasma fish-net etc, widen frequency band from GHz to THz and IR.Left-handed metamaterial is an arrangement of artificial structural elements designed to achieve advantageous and unusual properties. Under electromagnetic wave excitation, artificial structural element can be seen as atoms when the wavelength is much longer than the scale of single structural element, so single structural element can responded to electromagnetic properties of the artificial structural elements.In this paper, the constructional design was investigated. By the analytical and numerical studies ,a efficient and systemic schematic studies were proposed, included establish single structural element mode , Electromagnetic parameter retrieval from scattering (S) parameters, finite-difference-time-domain (FDTD) simulations , full wave wedge-shaped analysis simulations on realistic refraction index .A novel opposite Split ring resonators was presented by analysis of electromagnetic field and mode of resonance, it is investigated to show their negative refraction at the two frequency bands ,and the result is verified by full wave wedge-shaped analysis simulations.The controllable Left-handed metamaterials structure is another focus of my research. A planar metamaterials structure using liquid crystals sandwiched between layers of split ring resonators was demonstrated. This optimized structure has tunable negative index of refractive on account of a controlled permittivity of the liquid crystals drived by extend field. The frequency range with negative index of refractive can be adjusted conveniently and reversibly. Numerical simulation and analyzation show this is a valid and valuable Left-handed metamaterials structure.