  In this paper, we study Klein tunneling in random media. To this purpose, we
simulate the propagation of a relativistic Gaussian wavepacket through a
graphene sample with randomly distributed potential barriers (impurities). The
simulations, based on a relativistic quantum lattice Boltzmann method, permit
to compute the transmission coefficient across the sample, thereby providing an
estimate for the conductivity as a function of impurity concentration and
strength of the potentials. It is found that the conductivity loss due to
impurities is significantly higher for wave-packets of massive particles, as
compared to massless ones. A general expression for the loss of conductivity as
a function of the impurity percentage is presented and successfully compared
with the Kozeny-Carman law for disordered media in classical fluid dynamics.
