Research On Omnidirectional Infrared Narrow Dual-band Metamaterial Absorber

Metamaterial is a kind of composite unit structure which metal and dielectric materials are periodic arrangement and stacked each other.This artificial material has many physical and chemical properties different from conventional materials in nature.It has excellent application prospects in the fields of physics,materials science,biological detection,infrared imaging,signal interaction,secure communication,and laser guidance.Especially in recent years,with the deepening of research,more and more researchers focus on this research field.By studying the absorption characteristics of metamaterial absorber,the resonance absorption mechanism of metamaterial absorber is analyzed based on impedance matching theory.Aiming at the narrow-band dual band absorber,which is less studied in the research field at home and abroad,by changing the geometric size of the structure and the selection of different materials,the half peak width of the traditional metamaterial absorber,how to realize omnidirectional absorption,and the construction of a new metamaterial absorber structure are deeply studied.Based on the time domain finite difference algorithm,the electromagnetic absorption characteristics of various metamaterial absorbers are calculated by using FDTD solutions software.This paper mainly focuses on the narrow-band dual band absorber in the current research field at home and abroad.Its working wavelength is mainly for the mid infrared band,and through analysis the absorption mechanism of the single band absorber in finally,the omnidirectional dual band narrow band metamaterial absorber is realized.The main contents of this paper are as follows:1.A cross structure absorber with single band and narrow frequency band which can achieve high absorptivity in the mid infrared band is designed.Through the variable simulation of the geometric parameters of the metamaterial structure and the analysis of the field energy level distribution of the metamaterial structure,the influencing factors of the absorption characteristics of the single band absorber are studied.Based on the above research,a layered stacked traditional cross structure metamaterial absorber which can produce dual band absorption effect is designed.The results show that the absorber can produce two resonance absorption peaks with narrow half peak width and high absorptivity in the mid infrared band.The absorption characteristics of this kind of metamaterial structure are analyzed,which provides theoretical support for the further optimization design of traditional metamaterial structure.2.Based on the research of layered stacking structure,a nested cross structure embedded in the dielectric layer with extremely narrow half peak width and excellent frequency selection characteristics is designed.Through the analysis of the field level resonance mode,the mechanism of multi band absorption is found by using nested structure to realize multiple absorption modes in the same period.It provides a theoretical basis for the next study of omnidirectional narrow-band dual band resonance absorption.3.Based on the research of multi-mode absorption,the absorption mechanism of omnidirectional structure is analyzed.It is found that omnidirectional absorption is easier to realize only when the periodic structure is an independent unit structure or the field of resonance absorption in the unit structure is a discontinuous field.Through in-depth research,it is found that when the continuous field is broken,the field enhancement effect is significantly reduced,and the resonance absorption peak is also small.In this case,the half peak width of the resonance absorption peak in the unit cycle can realize narrow-band absorption also.4.Aiming at the problems of low metal activity and significant thermal damping effect caused by oxidation in the current frequency selective metamaterial absorber,two new semiconductor metamaterial structures are proposed.The first is the metamaterial structure based on the sandwich structure of graphene instead of metal structure,and the second is the novel semiconductor metamaterial structure using gallium arsenide instead of single-layer graphene.The research results show that these two structures can realize the dual band metamaterial structure with extremely narrow half peak width,and are extremely insensitive to the polarization angle and incident angle.they have extremely high application prospects in the fields of frequency selection,thermal imaging detectors,etc.