▎ 摘　　要

In this paper, a tunable multiband band-stop filter based on single-layer and few-layer doped periodically graphene rings is designed at THz wavelength. The performance of the proposed structure is calculated by using the finite-difference time-domain method. The metamaterial structure is comprised of the concentric graphene ring resonators printed on substrate layer of silica medium. The multiband band-stop filter can be achieved by adjusting the numbers of graphene ring resonator. More importantly, a dynamically tunable filter can be designed by adjusting the applied voltage or chemical potential doping to manipulate graphene's Fermi energy. The z-component electric field is investigated to explain the physical mechanism of the transmission. In addition, the proposed filter has the advantage of independence to polarization and insensitivity to the angles of the incident wave. Our design can have potential applications in various fields of tunable photonic devices, sensors and multi-band communication.