The Research Of Terahertz Linear Polarization Converter Based On Metamaterials

Terahertz(THz)radiation is electromagnetic radiation with a frequency between microwave and far-infrared light.Its frequency range is from 0.1 THz to 10 THz.Polarization is an important feature of electromagnetic waves.Polarization converters are used to control the terahertz wave polarization.The important device of the state belongs to the research hotspot of terahertz devices at home and abroad.Metamaterials are artificially designed materials with periodic structure,which can attract the attention of many special effects such as negative dielectric constant,negative magnetic permeability and negative refractive index which are not possessed by many natural materials.This paper studies and designs linear-polarized converters based on metamaterials,which has important theoretical research value and practical significance.The paper first analyzes the research background of terahertz linear polarization converter and the research status at home and abroad,and summarizes the problems faced.The basic principle of polarization conversion of linear polarization converter based on metamaterial is studied by using equivalent medium and equivalent impedance theory.The polarization conversion characteristics of linear polarization converter based on open resonant ring structure are analyzed.Using CST MWS 2017 electromagnetic simulation software,three terahertz supermaterial linear polarization converters based on split resonant ring(SRR)structure were designed.The influence of the main geometric parameters of metamaterials on polarization conversion characteristics was discussed.Among them,the first one is too The top structure of the Hertz linear polarization converter is composed of two open rings of different opening modes,with a frequency bandwidth of more than 80% polarization conversion rate of 1.0343 THz;the top structure of the second terahertz linear polarization converter It is composed of an open square ring and a metal grid.The frequency bandwidth with a polarization conversion ratio of 80% or more is 0.9492 THz.The top structure of the third polygonal terahertz linear polarization converter is composed of twofold lines with 92%.The frequency bandwidth of the above polarization conversion rate is 0.8180 THz.The three terahertz linear polarization converters were designed and tested.The simulation results were compared with the test results.The causes of the errors were analyzed,and the structure of the polarization converter with the largest error was improved and processed,testing,and obtaining a terahertz linear polarization converter that meets the design requirements.The terahertz linear polarization converter designed in this paper has good polarization conversion performance and can realize high-efficiency broadband linear polarization conversion.