Characterization of Graphene FET based 200 GHz Mixer and 1 GHz Amplifier Integrated on a Si Substrate
Konferensbidrag (offentliggjort, men ej förlagsutgivet), 2018
arises for new materials and technologies which can be used
in the millimeter wave and terahertz wave regime. In this
context, a receiver is an important component to be developed.
It converts the received signals into useful information. A
typical heterodyne receiver consists of an antenna, RF and IF
filters, RF and IF amplifiers, and a mixer. The amplifiers and
the mixer can be based on field effect transistors (FETs). To
obtain high speed transistors the charge carrier mobility and
velocity in the transistor channel should be high. Therefore,
the 2D material graphene is an interesting material since it has
a high room temperature charge carrier mobility and a high
saturation velocity .
In previous works a 10 dB small-signal amplifier designed for
1 GHz  and a 185-215 GHz subharmonic resistive mixer
 (designed for a center frequency at 200 GHz) based on
graphene FETs (GFETs) have been demonstrated.
The amplifier was further developed in  and the lumped
inductor for matching used in  was replaced by an planar
inductor. The measured and modeled gain for the two inductor
types are shown in Fig. 1. The gain is reduced from 10 dBm to
5 dBm when using the planar inductor compared to the lumped
inductor. The model shows that the gain can be increased to the
designed gain of 10 dBm if the inductor resistance is reduced
to Rs =5
by increasing the thickness of the gold conductor
to 2 m.
Additionally, the mixer design in  has been improved
compared to the mixer design in  by decreasing the loss
in the coplanar waveguid (CPW) circuit using air bridges.
In this work, both, the amplifier and mixer are integrated
together on a single silicon substrate and the characterization
results are presented.