CONTROLLABLE W-SHAPED THREE-PORT GRAPHENE-BASED CIRCULATOR IN THE THZ BAND

摘要

The invention in question comprises a W-geometry three-port graphene-based circulator operating in the THz region. The circulator may be described as a non-reciprocal passive component, the purpose of which is to transmit the electromagnetic signal inserted via a given inlet port and to lead this signal to another, outlet port after the application of an external DC magnetic field, thereby isolating a third port. The present invention may be used as a device in the protection of electromagnetic sources against undesired reflections originating from the outlet port which will be led to the port which has been isolated. This device comprises three waveguides made from graphene diffused by a circular resonator also made from graphene on an SiO₂ and Si substrate. The operating principle of this device is based on the propagation of plasmon waves at the graphene/dielectric interface in the THz region. After an electromagnetic wave is directed at one of the inputs of the waveguide, the structure exhibits a high level of confinement of the guided wave in the graphene band, thereby exciting surface plasmon polariton (SPP) resonances in the resonator, also made of graphene, thereby acquiring the dipole field profile which may be oriented in accordance with the applied DC magnetic field signal. The central frequency of the device and also the features thereof may be controlled by varying the chemical potential of the graphene resonator.