  The paradigm of graphene transistors is based on the gate modulation of the
channel carrier density by means of a local channel gate. This standard
architecture is subject to the scaling limit of the channel length and further
restrictions due to access and contact resistances impeding the device
performance. We propose a novel design, overcoming these issues by implementing
additional local gates underneath the contact region which allow a full control
of the Klein barrier taking place at the contact edge. In particular, our work
demonstrates the GHz operation of transistors driven by independent contact
gates. We benchmark the standard channel and novel contact gating and report
for the later dynamical transconductance levels at the state of the art. Our
finding may find applications in electronics and optoelectronics whenever there
is need to control independently the Fermi level and the electrostatic
potential of electronic sources or to get rid of cumbersome local channel
gates.
