Research on terahertz reflectarray based on graphene surface and PET substrate

Complex surface conductivity at THz frequencies allowing the propagation of relatively slow plasmonic modes results from the unique electronic band structure of graphene, which is followed by a drastically reduced electrical size of the array unit cell and thereby reconfigurable performance. The reflectarray element based on silicon dioxide substrate and Boron Nitride substrate has been developed in our lab. The extraordinary properties of graphene would be damaged once coating the silicon dioxide with graphene due to its rough surface. Moreover, the processing thickness of silicon dioxide in reality should be thicker than that in theory. Thus, a design of graphene reflective cell based on PET (Polyethylene Terephthalate) substrate at terahertz would be illustrated in this paper. Ansoft HFSS software is used to simulate and optimize the proposed structure. It is manifest that a full range of 0°~360° can be successfully achieved for the reflection phase at 1.095 Thz. In practice, the magnitude of reflection coefficient should be larger than 0.7 as a requirement to guarantee the efficiency of reflectarray. Additionally, the reflectarray has been implemented with properly arranged and biased graphene reflective cells. The method mentioned above is regarded as a qualified one to meet reflection coefficients and enable the accomplishment of beam scanning characteristics.