Research On Terahertz Metamaterial Resonators And Characteristics Based On Split Ring And Square Structure

Being in a special position in the electromagnetic spectrum,terahertz waves have many unique electromagnetic properties.However,relatively few substances naturally occurring in nature can respond to terahertz waves.In recent years,metamaterials have attracted much widespread attention.The emergence of metamaterials has provided a new way to utilize and manipulate terahertz waves,and people can design substances that respond to terahertz waves by artificially controlling the size and arrangement of the structure.At present,metamaterials are widely used in wave-absorbing stealth,electromagnetic protection,filtering,sensing,imaging,and other related fields,demonstrating the value of important applications.This paper conducts relevant research on terahertz electromagnetic metamaterials,four types of terahertz metamaterials and a terahertz metamaterial biosensor based on Electromagnetically Induced Transparency-like are proposed,and the main research contents are as follows:(1)Using the tiling method,a dual-frequency absorber and a quadruple-frequency absorber were designed based on the circular split-ring structure.Under TE mode,the absorption rate of both absorption peaks of the dual-frequency absorber exceeded99.9%,and the absorption rate of all four absorption peaks of the quadruple-frequency absorber exceeded 98.8%.Based on the circular split and square ring structure,a polarization-independent four-frequency absorber and a six-frequency absorber are designed.The absorption rates of the four absorption peaks of the polarizationindependent four-frequency absorber exceed 99%.The absorption rates of the six absorption peaks of the polarization-independent six-frequency absorber exceed 95%.(2)A metamaterial biosensor consisting of a combination of a square cut line and a circular split-ring resonator is proposed based on Electromagnetically Induced Transparency-like.The sensor achieves Electromagnetically Induced Transparencylike effect through the coupling between bright and dark modes to produce phase extinction interference,and a transparency window appears at 1.217 THz,effectively reducing the radiation loss with a Q value as high as 16.1.The resonance peak offset of this sensor saturates when the thickness of the analyte on its surface exceeds 14 μm,in which case the sensitivity of the transparent peak of this sensor is obtained up to281.25 GHz/RIU when the refractive index of the analyte n is increased from 1 to 1.6,corresponding to a quality factor FOM of 3.72.The sensor sample was prepared by experiments,and the results showed that the experimental results were consistent with the simulation results to a certain extent.