Research On Tunable Terahertz Metamaterial Filter Based On Liquid Crystal

Metamaterials was the US "Science" magazine evaluated the past ten years the most significant technological breakthroughs of humanity.With the rapid development of information technology,metamaterials gradually into the application level.However,due to the extraordinary electromagnetic properties of metamaterials is mainly determined by the shape and physical dimensions of the ordered structure units artificially designed,which make exhibit electromagnetic properties is confined to live.Therefore,researchers are paying more and more attention on the study of resonant properties of the tunable metamaterials.Liquid crystal,it's permittivity can be controlled by applying a voltage,which makes it very suitable for applications of tunable terahertz metamaterials.Based on this,we propose two different metamaterial filters based on the liquid crystal.The terahertz metamaterial narrow-band filter based on liquid crystal is composed of the circular-ring deep-slot array embedded with liquid crystal materials,and the liquid crystal material achieve the tuning function.The structure of filter is optimized by changing the inner and outer radius and thickness of the metal using the simulation soft based on finite element method,then a narrow band-pass filter with better performance is obtained.The influence of the polarization state and incident angle on the terahertz metamaterial filter is investigated by changing the incident electromagnetic angle and TE wave,TM wave and the filter work in the wide angle of incident and is not affected by the incident wave polarization state.The narrow-band filter was analyzed the performance.Effects of different liquid crystal on the frequency selection range and phase variation were investigated by injecting DFLC liquid crystal and LC1825 liquid crystal into circular-ring deep-slot array.The terahertz wide-band filter based on liquid crystal is a multi-layer metamaterial with the same metal shape but different size structure.The wide-band filter is composed by closed-ring resonator array and the liquid crystal achieving the tuning function was embedded between two quartz substrates.The structure of filteris optimized by changing the width and size of CRR,and the thickness of structure using simulation soft based on finite element method,then a wide-band filter with better performance is obtained.We also analyze the surface current and magnetic filed.Influence of the polarization state and incident angle on the terahertz metamaterial filter is investigated by changing the incident electromagnetic angle and TE wave,TM wave.Performance of broad-band filter was analyzed: the frequency range is 563.2GHz,the inhibition within the band reached 95%,and the rising and falling edge are 1000% and 857%,respectively.Finally,the effects of different liquid crystal on the frequency selection range were investigated by injecting LC1825 liquid crystal and 5CB liquid crystal between two quartz substrates.