Papers by Ali azar Safari
Analog Integrated Circuits and Signal Processing, 2020
A ring oscillator is an important circuit used to evaluate the performance limits of any digital ... more A ring oscillator is an important circuit used to evaluate the performance limits of any digital technology. The advantages of Graphene field effect transistor (GFET) over current CMOS technologies make it a prominent candidate for future highperformance electronics. In this paper, a GFET model is implemented in Verilog-A, and GFET design and analysis of a ring oscillator are performed using advanced design system (ADS) tool. By using GFET ring oscillator, the designed circuit is simulated using a 0.18 lm GFET process in ADS environment. The results show that the power consumption is 9.98 mW, while the VCO generates 24.12 GHz at 1 V. The effect of Graphene channel length variations on the frequency span, power dissipation and phase noise of GFET ring oscillators are studied. The main performance characteristics of the ring oscillator are compared with CMOS technology. It is shown that a GFET ring oscillator gives a higher oscillation frequency and has more power dissipation.
Monolayer Graphene Field Effect Transistor-Based Operational Amplifier
Journal of Circuits, Systems and Computers, 2019
Graphene Field Effect Transistor (GFET) is a promising candidate for future high performance appl... more Graphene Field Effect Transistor (GFET) is a promising candidate for future high performance applications in the beyond CMOS roadmap for analog circuit applications. This paper presents a Verilog-A implementation of a monolayer graphene field-effect transistor (mGFET) model. The study of characteristic curves is carried out using advanced design system (ADS) tools. Validation of the model through comparison with measurements from the characteristic curves is carried out using Silvaco TCAD tools. Finally, the mGFET is used to design a GFET-based operational amplifier (Op-Amp). The GFET Op-Amp performances are tuned in term of the graphene channel length in order to obtain a reasonable gain and bandwidth. The main characteristics of the Op-Amp performance are compared with 0.18[Formula: see text][Formula: see text]m CMOS technology.
Distributed Amplifier Based on Monolayer Graphene Field Effect Transistor
Journal of Circuits, Systems and Computers, 2019
Due to the ultra-high carrier mobility and ultralow resistivity of Graphene channel, a Graphene f... more Due to the ultra-high carrier mobility and ultralow resistivity of Graphene channel, a Graphene field effect transistor (GFET) is an interesting candidate for future RF and microwave electronics. In this paper, the introduction and review of existing compact circuit-level model of GFETs are presented. A compact GFET model based on drift-diffusion transport theory is then implemented in Verilog-A for RF/microwave circuit analysis. Finally, the GFET model is used to design a GFET-based distributed amplifier (DA) using advanced design system (ADS) tools. The simulation results demonstrate a gain of 8[Formula: see text]dB, an input/output return loss less than [Formula: see text]10[Formula: see text]dB, [Formula: see text]3[Formula: see text]dB bandwidth from DC up to 5[Formula: see text]GHz and a dissipation of about 60.45[Formula: see text]mW for a 1.5[Formula: see text]V power supply. The main performance characteristics of the distributed amplifier are compared with 0.18[Formula: se...
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Papers by Ali azar Safari