Nonreciprocal dynamically tunable power dividers by three (1x3) based on graphene for terahertz region

Abstract

This paper presents two new types of dynamically tunable THz nonreciprocal power dividers based on graphene. These components fulfill division of the input power between three output ports. Besides, they possess isolation properties, i.e., a source connected to the input port is protected against unwanted reflections from the output ports. The components consist of a disk-shaped graphene resonator and six graphene waveguides connected to it. The graphene elements are deposited on a dielectric substrate. The resonator is subject to an external electric and DC magnetic field. The dipole mode resonance in the magnetized resonator is excited by surface plasmon–polariton waves propagating in the graphene waveguides. Numerical simulations and the analytical temporal coupled-mode theory are used in the analysis. The division level of the input power between the three output ports of dividers is about −8 dB and the isolation of the source in relation to the output ports is higher than −15 dB with the central frequency 7.45 THz and the bandwidth 3%. DC magnetic field is 0.29 T and Fermi energy is 0.15 eV. The central frequency of the dividers can be dynamically adjusted by an external electric field.