Terahertz (THz) communication is envisioned as a key wireless technology to satisfy the need for 1000x faster
wireless data rates. To date, major progress on both electronic and photonic technologies are finally closing the
so-called THz gap. Among others, graphene-based plasmonic nano-devices have been proposed as a way to enable
ultra-broadband communications above 1THz. The unique dynamic complex conductivity of graphene enables
the propagation of Surface Plasmon Polariton (SPP) waves at THz frequencies. In addition, the conductivity of
graphene and, thus, the SPP propagation properties, can be dynamically tuned by means of electrostatic biasing
or material doping. This result opens the door to frequency-tunable devices for THz communications. In this
paper, the temporal dynamics of graphene-enhanced metallic grating structures used for excitation and detection
of SPP waves at THz frequencies are analytically and numerically modeled. More specifically, the response of a
metallic grating structure built on top of a graphene-based heterostructure is analyzed by taking into account
the grating period and duty cycle and the Fermi energy of the graphene layer. Then, the interfacial charge
transfer between a metallic back-gate and the graphene layer in a metal/dielectric/graphene stack is analytically
modeled, and the range of achievable Fermi energies is determined. Finally, the rate at which the Fermi energy in
graphene can be tuned is estimated starting from the transmission line model of graphene. Extensive numerical
and simulation results with COMSOL Multi-physics are provided. The results show that the proposed structure
enables dynamic frequency systems with THz bandwidths, thus, enabling resilient communication techniques
such as time-hopping THz modulations.
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