Design and Simulation of a Frequency Doubler Using Graphene Nanoribbon Field Effect Transistors for Communication Devices

Abstract

Modeling of a graphene nanoribbon field effect transistor (GNRFET) as a frequency doubler has been extensively explored for developing future communication applications. For its analysis, different types of modifications are applied to the GNRFET model simulated in a Hewlett simulation program with an integrated circuit. The model is demonstrated for its frequency response and conversion gain. It uses an intrinsic GNRFET for frequency doubling which clearly shows a distortionless sinusoidal output at a peak frequency of 20.6 MHz for an applied input of 10.3 MHz. However, after applying doping at different fractions of 0.3%, 3% and 30% in the transistor model, signal decay appears at 30% doping fractions. Results are also shown for increasing the number of dimers (N), increasing the number of channels for conduction and the impact of changing the dielectric constant on the doubler model performance. It is found that as the channel width increases, an increase in the conversion gain from − 26.05 dB to − 20 dB results from an increase in N from 8 to 20 dimer lines. Further, if four graphene nanoribbon (GNR) channels are used in the doubler operation instead of one GNR channel, then a high conversion gain of − 16.47 dB as compared to − 26.05 dB for an individual GNR channel is also calculated. Regarding the impact of different dielectrics, it is revealed that, similar to a conventional transistor, a graphene transistor with a high-K-value dielectric presents the highest gain, but with a high distortion in the output signal. However, using a conventional silicon dioxide (SiO₂) dielectric having a low K value gives lower conversion gain, but ideal frequency doubling in the output is attained.