Graphene-based four-port THz circulator

We propose an approach for the design of graphene-based four-port circulator for THz region. The device presents a three-layer structure consisting of layers of graphene, silica (SiO
₂
) and silicon (Si). The in-plane figure of the circulator consists of a circular graphene resonator and two waveguides laterally coupled to it. The device is magnetized by an external DC magnetic field normal to the plane of the resonator. The working principle of the device is based on the dipole resonance of the magnetized graphene resonator. Numerical calculations demonstrate the isolation greater than -15 dB and the insertion loss better then -3.5 dB within the bandwidth of about 4.65 % and the central frequency 5.17 THz for DC magnetic field of 0.8 T and Fermi energy ε
_F
= 0.15 eV.