  We theoretically study the electronic transport properties of Dirac fermions
through one and double triangular barriers in graphene. Using the transfer
matrix method, we determine the transmission, conductance and Fano factor. They
are obtained to be various parameters dependent such as well width, barrier
height and barrier width. Therefore, different discussions are given and
comparison with the previous significant works is done. In particular, it is
shown that at Dirac point the Dirac fermions always own a minimum conductance
associated with a maximum Fano factor and change their behaviors in an
oscillatory way (irregularly periodical tunneling peaks) when the potential of
applied voltage is increased.
