Research On Electromagnetic Properties And Frequency Selective Method Of Graphene Films

Graphene due to its unique electronic structure and excellent physical,chemical and mechanical properties,as environmentally friendly,transparent material exhibits great promise in high-tech civilian products and national demand.Firstly,in this paper we study the optical properties and electromagnetic shielding properties of graphene films as transparent shielding materials.We measure the transmittance of visible light and the properties of reflection,transmission and absorption in X band of different square resistance graphene.We find that the transmittance of light in the range of 400nm~700nm for three kinds of graphene(300?/?,556?/?,1099?/?)are all above 90%.It shows that graphene has good light transmittance.In X band,the S21 parameters is about-3.9 dB,-3.16 dB and-1.92 dB,whereas the S11 parameters is about-8.6dB,-10.7dB and-14.49 dB,respectively.Further we prepare graphene,which has the square resistance of 20?/?.The shielding effectiveness of graphene is about 13.5 dB.Secondly,We design and simulate graphene frequency selective surface(FSS)with high frequency structure simulator(HFSS).We analysis cross aperture,circular and dipole FSS's frequency response with different unit structure,period,thickness of medium.It shows that when the graphene layers are increased,the resonant frequency is shifted to higher frequency.When changing the structure of graphene films,with the width of cross aperture increased,the bandwidth of graphene FSS becomes wider.When the medium loading mode is changed,the resonant frequency of bilateral medium loading's frequency response characteristic is shifted to lower frequency.These results show that graphene has good electromagnetic properties,which lays the foundation for the future development of lightweight device.Finally,the structure of graphene FSS and transmission characteristics is obtained by laser etching and vector network analyzer with small window test system,respectively.By comparing the results of simulation and measurement,the validity of graphene FSS simulation are verified.It indicates that the quality of graphene has an important influence onfrequency selection devices.The result provides significant guidance in designing graphene FSS.