Design Of Transparent Tunable Absorber Based On Graphene

As a functional device for absorbing electromagnetic waves,the wave absorber has a high application value in military stealth and civil communication,and has become a hot topic in the field of electromagnetic research.Graphene,as a two-dimensional plane material,has high electronic mobility,low resistivity,optical transparency,and is widely used in electronic devices.Adding graphene in the field of wave absorption can broaden the wave absorption bandwidth,reduce the device thickness,and increase the tunability,providing a broader application field for the wave absorber.Therefore,this paper studies the wave absorber based on graphene to realize its tunability,optical transparency and the dependence on the polarization angle under different application backgrounds.The main research contents are as follows:(1)Single-frequency,double-frequency and wide-band tunable absorber are designed based on the square symmetry structure,and the transparent electrode material ITO is used instead of the traditional metal to realize the transparent characteristics of the absorber.First,A square-structured graphene single-frequency adjustable wave absorber is designed,The absorber enables the perfect absorption of electromagnetic waves at 14.85 GHz,By changing the graphene Fermi energy level,With adjustable absorption amplitude;Based on a square structure,By patterned graphene layer structure,simultaneously tunable with two band absorption amplitude,The absorption range can be adjusted from 99.01% to 18.67%,and99.59% to 19.43%,respectively,The switch between electromagnetic waves from absorption and reflection can be realized;Change the square structure design of the square ring broad-band tunable absorber,Relative wave absorption bandwidth is up to 78.98%,Add a circular ring structure to this basis,Increase of relative wave absorption bandwidth to 89.43%.(2)The polarization-sensitive transparent absorber is designed on the basis of the T-type unit structure to realize the single frequency,double frequency and three-frequency band wave absorption of the absorber.By introducing a new control dimension to the absorber,the central frequency and absorption amplitude can be adjusted.Firstly,the transparent absorber based on single T structure is designed for single frequency absorption in microwave band,proposed T-T-type and field type absorber with simple harmonic structure,realized two-frequency and three-frequency absorption in microwave band,analyzes the principle of different absorption band number,and obtained single,double and three-frequency absorption effects in the THz band.Add graphene material to the center of the microwave segment T-T wave absorber,Realize the simultaneous tuning of the dual-frequency band center frequency points,From 9.13 GHz to 8.98 GHz and 10.62 GHz to 10.56 GHz,respectively,Add the graphene material at the long edge of the T-T-type structure,Simultuning double band absorption amplitude,From 98.68%to 56.88%,respectively,99.22%is adjusted to 53.67%;Add a graphene material at the long edge of the terahertz-band T-T-type structure,Realize the simultaneous tuning of the dual-frequency band center frequency points,From 4.02THz to4.48THz,,respectively 4.78THz transferred to 5.17THz;Introduce graphene into the field-type structure,Tuning of the three-frequency band absorption amplitude in the microwave section,Adjust from 97.57%to 87.29%,96.46%to 81.63%,and 99.58%to80.47%,respectively,THz band enables simultaneous tuning of three-frequency band central frequency points,Adjust from 3.03THz to 3.61THz,3.47THz to 4.06THz and 4.56THz to5.12THz.,respectively.