We investigate the effect of spatial dispersion phenomenon on the performance
of graphene-based plasmonic devices at THz. For this purpose, two different
components, namely a phase shifter and a low-pass filter, are taken from the
literature, implemented in different graphene-based host waveguides, and
analyzed as a function of the surrounding media. In the analysis, graphene
conductivity is modeled first using the Kubo formalism and then employing a
full-kρ model which accurately takes into account spatial dispersion. Our
study demonstrates that spatial dispersion up-shifts the frequency response of
the devices, limits their maximum tunable range, and degrades their frequency
response. Importantly, the influence of this phenomenon significantly increases
with higher permittivity values of the surrounding media, which is related to
the large impact of spatial dispersion in very slow waves. These results
confirm the necessity of accurately assessing non-local effects in the
development of practical plasmonic THz devices.Comment: 5 pages, 18 figures, 2 table
