Design and simulation of tunable metal-graphene hybrid metamaterial terahertz modulator based on electromagnetically induced transparency

In this paper, we propose a tunable metal-graphene hybrid metamaterial modulator based on the electromagnetically induced transparency (EIT) effect, which can be applied in the terahertz modulation field. The device consists of a U-shaped sliver strip and a rectangular sliver ring. The proposed structure is coupled by bright-bright EIT mode to generate a narrow-band electromagnetically induced transparent window. In the modulation process, the transparent window only changes in amplitude, keeping the resonant frequency constant and improving the device’s resistance to interference. Active tunability is achieved by adjusting the bias voltage to alter the Fermi level of the graphene film layer, thereby facilitating modulation performance adjustment. The transparent window has a narrow bandwidth of 0.053 THz, with the transparent peak located at 0.773 THz. The maximum modulation depth of the proposed device is 74.1% and the maximum positive group delay in the transparent window can reach 0.01 ns. The designed structure has the advantages of terahertz modulation and slow light field due to its narrow-band tunability. This work provides a potential solution for electromagnetic wave control for 6G wireless communication.