  We study a possible circuit solution to overcome the problem of low voltage
gain of short-channel graphene FETs. The circuit consists of a fully
differential amplifier with a load made of a cross-coupled transistor pair.
Starting from the device characteristics obtained from self-consistent
ballistic quantum transport simulations, we explore the circuit parameter space
and evaluate the amplifier performance in terms of dc voltage gain and voltage
gain bandwidth. We show that the dc gain can be effectively improved by the
negative differential resistance provided by the cross-coupled pair. Contact
resistance is the main obstacle to achieving gain bandwidth products in the
terahertz range. Limitations of the proposed amplifier are identified with its
poor linearity and relatively large Miller capacitance.

Mesoscale and Nanoscale Physics