  This paper aims to study the magneto-plasmons in an anisotropic graphene
nano-waveguide with bigyrotropic cover and substrate. The substrate is backed
by a perfect electromagnetic conductor (PEMC) layer, a general and ideal
boundary, which can be transformed easily into the perfect electric conductor
(PEC) or the perfect magnetic conductor (PMC) boundaries. The upper and bottom
layers of the graphene sheet are made of different magnetic materials. The
external magnetic field is applied perpendicularly to the structure surface,
which can be provided by a permanent magnet placed underneath the ground plane.
Hence, the graphene sheet has anisotropic conductivity tensor. A novel
analytical model has been proposed for the general nano-waveguide to find its
propagation properties. As special cases of the proposed general structure, two
important new waveguides have been introduced and studied to show, first the
richness of the proposed general nano-waveguide regarding the related specific
plasmonic wave phenomena and effects, and second the validity and the high
accuracy of the proposed model. The analytical and the simulation results are
in an excellent agreement. It is shown that the modal properties of the
proposed structure can be tuned effectively via the external magnetic field and
the chemical potential of the graphene. Harnessing the non-reciprocity effect
of anisotropic materials and the graphene sheet, the presented analytical model
can be exploited to design tunable innovative devices in THz frequencies.
