Research On Terahertz Band Stop Filter Based On Vanadium Dioxide Metamaterial

With the development of terahertz technology,more and more related applications have begun to enter our lives.The imperfection of terahertz devices has restricted the development of terahertz technology.Therefore,the research on terahertz devices has caused widespread concern.THz devices with wider frequency bands and better filtering performance also have greater requirements.In response to this need,this paper uses a regular hexagonal split-ring resonance as the basic structure of the filter,and evolves a mirrored regular hexagonal split-ring resonance and a double-layer mirrored regular hexagonal split-ring resonance.The characteristics of terahertz band-stop filters of these three structures are studied by modeling and simulation of three-dimensional electromagnetic field software HFSS.The control variable method was used to analyze the influence of its structural parameters on the filtering performance,including metal line width,cell structure size,substrate area,cell arrangement pitch,and substrate thickness.The performances of three terahertz band-stop filters are compared.On the basis of this,it is proposed to fill the opening of the regular hexagonal resonance ring with the vanadi?m dioxide phase change material.Utilizing the phase change characteristics of vanadi?m dioxide,the terahertz filter has a band pass or band stop function under different temperature conditions.Realize the adjustable function of the terahertz filter.Three terahertz filters based on vanadi?m dioxide metamaterials were simulated and analyzed.The main research contents of the paper are as follows:(1)A regular hexagonal split-ring resonance structure is designed.Through optimization of structural parameters through simulation,a better band-stop filter performance is obtained.The-20 dB stopband bandwidth reaches 50 GHz,and the modulation depth can reach-28.5dB.The center frequency is adjustable around 0.3THz by changing the metal line width and the unit structure size.(2)A mirrored regular hexagonal split-ring resonance structure is designed.By simulating and optimizing its structural parameters,better band-stop filtering performance is obtained.The-20 dB bandwidth can reach 60 GHz,the modulation depth can reach-30 dB,and the center frequency can be adjusted around 0.3THz.Its performance is better than the regular hexagonal split-ring resonance structure.(3)A double-layer mirrored regular hexagonal split-ring resonance structure is designed.By simulating and optimizing the structural parameters,better bandstop filtering performance is obtained.The-20 dB bandwidth can reach 150 GHz,the modulation depth can reach-41.5dB,and the center frequency can be adjusted around 0.3THz.This structure is the optimal structure.Compared with a general terahertz band-stop filter,it has a deeper modulation depth and a wider-20 dB bandwidth.In addition,a dual-frequency terahertz filter can be obtained by adjusting the thickness of the substrate.(4)A terahertz tunable filter based on vanadi?m dioxide metamaterial is proposed.Vanadi?m dioxide phase change material is embedded in the openings of the three structures mentioned above.The terahertz filter has two states of bandpass and bandstop at different temperatures.Simulation analysis results show that this feature can be used to develop terahertz switched filters.