Research Of Dual-Band Terahertz Negative Refraction Material

In recent years,as the terahertz technology has made great avdances in application fields such as imaging,safety testing,radar,wireless communications,biological medicine,astronomy,the use of left-handed materials to modulate terahertz waves is the current frontier of terahertz technology.Left-handed materials are artificial composite materials arranged by periodic subwavelength structure possessing unique electromagnetic properties nonexistent in natural materials,with the real part of permittivity and permeability are negative in the same frequency range,and the electromagnetic wave propagates according to the left-handed rule.Considering that the research of left-handed materials in terahertz frequency band is few,and the research of strong coupling stacked dual-band and multi-band performance of left-handed metamaterials is blank,in this dissertation,a new structure based on fishnet left-handed material is designed.It is applied to terahertz band,and its performance is discussed based on the simulation results.The main contents include:(1)The principle and design method of left-handed materials are described,as well as how to extract effective electromagnetic parameters from S parameters and analyze the properties of left-handed materials in combination with the distribution of electromagnetic fields.The the left-handed material with open resonant ring structure and fishnet structure were simulated,and a dual-band left-handed material for terahertz frequency range was designed based on the fishnet structure.The effects of the structural parameters and the incidence angle of the electromagnetic wave on the electromagnetic characteristics were studied.(2)The properties of left-handed materials under different stacking conditions are discussed,the effect of strong coupling stacking on the bandwidth and refractive index of the left-hand bands is emphatically introduced,the dual-band left handed material designed in this paper is used as the unit structure to construct the prism,the existence of negative refraction are verified through the simulation,the refractive index curve of the prism is calculated by the electric field distribution and the electromagnetic characteristics of the stacked left-handed materials are analyzed.