  Graphene plasmons have attracted significant attention due to their
tunability, potentially long propagation lengths and ultracompact wavelengths.
However, the latter characteristic imposes challenges to light-plasmon coupling
in practical applications, generally requiring sophisticated coupling setups,
extremely high doping levels and/or graphene nanostructuting close to the
resolution limit of current lithography techniques. Here, we propose and
theoretically demonstrate a method for alleviating such a technological strain
through the use of a practical substrate whose low and negative dielectric
function naturally enlarges the graphene polariton wavelength to more
manageable levels. We consider silicon carbide (SiC), as it exhibits a
dielectric function whose real part is between -1 and 0, while its imaginary
part remains lower than 0.05, in the 951 to 970 cm$^{-1}$ mid-infrared spectral
range. Our calculations show hybridization with the substrate's phonon
polariton, resulting in a polariton wavelenth that is an order of magnitude
longer than obtained with a silicon dioxide substrate, while the propagation
length increases by the same amount.
