Dual-Band Tunable Graphene Metamaterial Structures for Terahertz Biosensing Applications

In this paper, an absorption terahertz biosensor with tunable resonance point is designed based on graphene metamaterial. The structure achieves perfect absorption through graphene-dielectric-metal. The graphene unit structure consists of two semicircular resonators with line bar resonators, which produce narrow-band resonance peaks with absorption up to 99.9% at 0.43 THz and 0.65 THz, respectively, at a Fermi energy level of 0.8 eV. Simulation results show that the refractive index sensitivity of the dual-resonance biosensor is 120.6 GHz/RIU and 191.7 GHz/RIU. The resonance point of the biosensor can be adjusted within 0.3-0.8 THz by applying an external voltage. In addition, the biosensor is incidence angle insensitive and maintains a good absorption profile at an incidence angle shift of 60°. The designed tunable metamaterial biosensor has important applications in the fields of biomedical diagnosis and food safety.