Design Of Terahertz Absorber And Microwave Devices Based On Electromatgnetic Metamaterials

Electromagnetic properties of electromagnetic metamaterials such as double-negative,high-impedance surfaces and perfect absorption of electromagnetic waves are are mainly achieved through novel structures,sizes,and periodic arrangements..Electromagnetic properties of metamaterials are not only a new type of material,but also a great change in the design of traditional materials thinking.At the same time,it has a lot of potential applications in different fiels such as stealth cloak,perfect lens,ion sensor,radiant heat instrument,perfect light absorption and photodetector and so on.Based on the theory of plasma resonance and equivalent circuit theory,the working principle of graphene loading electromagnetic absorber and left-handed material loading microwave device is analyzed.Among them,the Kubo model and the Drude model of the conductivity of graphene were analyzed in the process of designing the electromagnetic absorber with the new carbon material graphene.Firstly,in the design of the terahertz absorber,due to the need to consider the polarization sensitivity,so the design follows the C4 rotation symmetry principle.Taking the graphene as the absorber pattern of the absorber,a four-arm rotationally symmetric terahertz absorber with tunable polarization is designed at 1.24THz frequency.The fractal theory is used to design a 0.5THz and 1.5THz frequency of the narrow-band dual-frequency polarization is not sensitive to the four-arm symmetrical structure of the graphene absorber;Finally,the use of double-frequency tunable to expand the bandwidth of the method,designed a 0.56THz to 1.37THz double Layer of copper coin-type fishing net structure of ultra-wideband graphene absorber.The polarization sensitivity,wide incidence angle and the tuning characteristics of each of the absorbers are demonstrated by spectral analysis.Secondly,in the microwave device design,starting from the symmetrical structure of the design ideas,designed a work in the 2-8GHz between the hollow collar collar symmetrical left hand structure,bow tie structure design increases the inductance on the loop,making the left hand.The size of the unit is greatly reduced,and the arc radius r and the parallel plate gap g are scanned.Due to the limited parameters of the uniform structure,the negative refractive index is low and the left-hand band is single and so on.So from the asymmetric structure,an asymmetric double-band absorption of the high-order note-shaped left-hand material is designed and scanned The length of the metal rod AO and the opening gap g,and finally the use of prism experiments to verify the asymmetric high-end note-shaped left-handed material negative refractive index characteristics.In the antenna application,in order to meet the S-band communication needs,the design of the hollow-type bow tie symmetrical left-handed structure loaded into the monopole broadband antenna,change the antenna radiation characteristics,increase the impedance bandwidth and impedance matching.The influence of three different connection modes on the return loss of monopole broadband antenna is analyzed and compared by the change of arc-to-inductance and capacitive-type interdigitated in double-arm connection.