Design And Research Of Terahertz High Sensitivity Sensor Based On Metamaterial

The terahertz wave can provide important information such as the electromagnetic characteristics of many substances by virtue of its low energy,wide band and good fingerprint spectral resolution ability,so as to achieve non-destructive detection of substances.In addition,terahertz waves can effectively enhance the sensitivity of detection,so it has important application value in the field of sensory detection.However,in actual detection,the amount of detection samples used is extremely small,which leads to a decrease in the sensitivity of the sensor.Therefore,the main goal of optimizing the terahertz sensor is to increase the sensitivity of the sensor.Metamaterials provide an effective way to achieve this goal.It can enhance the electromagnetic field locally and is very sensitive to changes in the dielectric properties of the external environment.In addition,effective control of electromagnetic waves can be achieved by adjusting the structural parameters of metamaterials.Therefore,combining the two can effectively improve the sensor’s sensing performance.In order to improve the sensing performance of terahertz sensors,this paper proposes two high-sensitivity sensors based on metamaterials,and conducts research and analysis on these two sensors through electromagnetic simulation software CST Microwave Studio.The main research contents are as follows:1.A terahertz high-sensitivity sensor based on Fano resonance is proposed.Its resonance unit is composed of double split ring resonators(DSRRs)and cut wires(CW).The coupling effect between the two substructures produces a typical asymmetric Fano line shape,which effectively reduces the radiation loss and makes the Quality factor improve.The Quality factor of the sensor is up to 83,the sensitivity of the sensor is about 171 GHz/RIU and the figure of merit(FOM)can reach 18.3.The equivalent circuit model is used to explain the sensing principle of the sensor,and the effect of the coupling distance between DSRRs and CW on the Quality factor is studied.On this basis,the tolerance characteristics and sensor performance of the sensor are studied,and the focus is on the sensitivity of the sensor to the thickness and refractive index of the analyte.2.A multi-band terahertz sensor is proposed,whose unit cell is composed of a symmetrical arch bridge structure and a metal short wire.The sensor has four discontinuous resonance modes at 0.789 THz,1.333 THz,2.019 THz and 2.878 THz,and the Quality factor are 16.47,32.53,58.25 and 169.3 in order.Through simulation analysis,the generation mechanism of multi-band and the influence of metamaterial structure parameters on the reflection spectrum were studied.In addition,the tolerance characteristics and sensor performance of the sensor are analyzed in detail,among which the focus is on the sensitivity of the sensor to the thickness and refractive index of the analyte.The final calculation shows that the sensor’s refractive index sensitivity can be up to 1.43 THz/RIU,and figure of merit(FOM)is as high as 87.68.Compared with other multi-band sensors,the Quality factor and sensitivity of the proposed sensor structure have been greatly improved,and it has important application value in the field of actual sensor detection.