  In this paper we present a higher-dimensional seesaw mechanism. We consider a
single, flat extra dimension, where a fat brane is localized and contains the
standard model (SM) fields, similar to Universal Extra Dimension models. There
is only one Dirac fermion in the bulk, and in four dimensions it results in two
towers of Kaluza-Klein (KK) Majorana sterile neutrinos, whose mass mixing with
the SM neutrinos is suppressed due to a brane-localized kinetic term. The
interaction between the sterile neutrinos and the SM is through the usual
coupling with the Higgs boson, where the coupling depends upon the
compactification radius $R^{-1}=10^{-2}-1$ GeV and the width of the fat brane
$L^{-1}=2$ TeV, where the latter value is chosen to avoid LHC constraints. Due
to this suppression mechanism the mass of the lightest sterile neutrinos can be
of order $\mathcal{O}(1-10)$~\text{TeV} while naturally explaining the small SM
neutrino mass, which in turn is easily obtained for a large range of parameter
choices. Furthermore, neutrino oscillations are not substantially influenced by
the tower of sterile KK particles. Finally, leptogenesis is investigated in
this setup, and it is viable for some values within the parameter space.
