Dynamically controllable graphene three-port circulator

A new type of the graphene-based three-port circulator is suggested and analysed. The cross-section of the component presents a three-layer structure consisting of a layer of silicon, of silica and of graphene. In-plane figure resembles a common microwave nanostrip circulator with a circular graphene resonator and three waveguides symmetrically connected to it. The graphene is magnetized normally to its plane by a DC magnetic field. The numerical simulation demonstrates the isolation of -15 dB and insertion losses of -2 dB in 6.98 \% frequency band with the central frequency 8.23THz.Comment: 7 pages, 5 figure

THz graphene W-shaped three-port circulator with dynamical control

We propose a new graphene-based THz circulator. It consists of a circular graphene resonator and three graphene nanoribbon waveguides of W-geometry placed on a dilectric substrate. Surface plasmon-polariton waves propagate in the waveguides. The nanoribbon excites in the resonator dipole resonance. Nonreciprocity of the device is defined by nonsymmetry of the conductivity tensor of the magnetized graphene. The circulator with the central frequency 7.5 THz has the bandwidth 4.25\% for isolation -15 dB, insertion loss -2.5 dB. Applied DC magnetic field is 0.56T and Fermi energy of graphene $\epsilon_F=0.15$eV. The Fermi energy allows one to control dynamically the circulator responses