Simulation And Experimental Study Of Terahertz Wave Regulation Based On Open Resonant Ring Metamaterial Structure

With the development of terahertz technology,more and more terahertz functional devices have been designed,applied and come into our life.However,the research on terahertz devices is not perfect enough,which limits the wider application of terahertz technology to some extent.In order to further study the regulation properties of terahertz wave and improve the regulation performance of terahertz devices,a variety of metamaterial structures were designed based on the "C" shaped open resonant ring.The influence of the metamaterial structural parameters(such as the thickness of metal layer,the thickness of substrate and the opening distance,etc.)on the terahertz wave transmission was analyzed by the control variable method using CST simulation software.The terahertz metamaterial samples were prepared according to the optimal structural parameters obtained from several simulation studies.The terahertz time domain spectrometer(THz-TDS)was used to test the transmission characteristics of the samples.The detected results are very close to the simulation results.In order to improve the flexibility of the terahertz wave regulation of the metamaterial structure,vanadium dioxide material is embedded in the opening of the resonant ring,and the band-pass or band-stop function of the terahertz filter is realized under different temperature conditions by using the phase transformation characteristics of vanadium dioxide.It has a wider modulation depth than the original metamaterial structure.The main contents of this paper are as follows:1.A metamaterial structure with square hole embedded in metal opening resonant ring based on silicon substrate was designed.Through simulation study,it was found that with the increase of metal layer thickness,the transmission peak position of metamaterial structure moved to high frequency,and the transmission rate decreased slightly.With the increase of substrate thickness,the position of transmission peak moves to low frequency,and the transmittance decreases with the increase of substrate thickness.As the increase of the opening distance,the position of the transmission peak moves to the high frequency,and the transmittance increases.2.Three kinds of open resonant ring metamaterial structures based on polyimide substrate were designed.Through simulation study,it was found that with the increase of metal layer thickness,the position of transmission peak of metamaterial structure moved to high frequency and the transmittance decreased slightly.With the increase of substrate thickness,the position of transmission peak moves to low frequency and the transmittance decreases to some extent.When the thickness of the substrate is large enough,the frequency of the transmission peak tends to a stable value.3.The terahertz wave transmission spectrum of single open resonant ring and double open resonant rings are obtained through simulation.The simulation results show that the number of transmission peaks increases with the increase of the number of open resonant rings.When there is only one open resonant ring,one transmission peak appears in the range of 0-2 THz.While there are two open resonant rings,two high transmission peaks appear in the range of 0-2 THz.Thus,one and two "C" shaped open resonant rings can be used to generate single-band and dualband transmission peaks.By adding more resonant rings to the unit structure,it is possible to improve the sensitivity of the terahertz detection device.4.According to the results of the simulation study,the optimal structural parameters were selected to study the preparation process of terahertz metamaterial samples,and the metamaterial samples were prepared.The terahertz time-domain spectrometer was used to test the transmission spectrum of the sample.It is found that the transmission rate curve and the numerical simulation results are basically identical,but the transmission rate falls,the analysis of the reason is that exist in the process of sample preparation size error,moreover in the process of sample testing,moisture from the environment of THz wave will have a certain degree of absorption.5.The transmission spectrum of the square resonant ring structure embedded with vanadium dioxide at different temperatures is studied.According to the simulation results,the modulation depth can reach 93.2%.The square resonant ring structure was divided into different basic structures,and the vanadium dioxide phase change material was embedded in the opening respectively.The band-pass and band-stop functions of the terahertz filter at different temperatures were studied,and their control effects were compared.It is found that the modulation depth of "field" structure can reach 95.9%,the modulation range is wider and the effect is the best.This study provides a reference for the development of terahertz filter.