Investigations On High Performance Graphene Frequency Selective Surfaces

Terahertz communication and detection system is one of the research hotspots in the field of electronics.Frequency selective surface is a common key component in terahertz system,in which the characteristic tunable frequency selective surface receives special attention because of its flexibility.Traditional electromagnetic materials and devices have limited tunability in the terahertz band,while new graphene materials show good electromagnetic control ability in the terahertz band.Therefore,in recent years,domestic and foreign scholars have conducted in-depth studies on the frequency selective surface of graphene,mainly focusing on its tunable properties.On this basis,this paper studied the frequency selective surface of tunable graphene with high frequency selectivity.The main research contents are as follows:1.A quasi-elliptic tunable band pass graphene frequency selective surface based on multi-mode resonator is proposed.The elements are divided into two resonators by means of the gap.When the main polarization wave is incident,the elements constitute a third-order transverse spatial filter.Three reflection zeros and two transmission zeros are designed based on the coupling resonator circuit theory to achieve high frequency selectivity.2.An antenna-filter-antenna structure based on bilateral steep roll-off tunable graphene frequency selective surface is proposed.By using the inverse characteristics of two coplanar waveguides in the middle nonradiating layer and coupling with the patches on both sides,a transmission zero is introduced into the upper and lower sideband respectively,and the flat fourth-order passband and bilateral steep roll-off characteristics are realized.3.A pass-band switched graphene frequency selective surface based on aperture coupled resonator is proposed.The electrical coupling between the cross resonators located on either side of the aperture is dominant.By adjusting the chemical potential of graphene,the electromagnetic field distribution at the end of the upper and lower resonators is controlled to achieve the on/off state of the passband.