Carbon Nanotube Field Effect Transistor (CNTFET) is cutting-edge technology where the demand for transistor scaling is increasing day by day industrially. Beyond 10 nm scaling of MOSFET is introducing several limitations like short channel effect, drain induced barrier lowering, less Ion/off ratio etc. Instead of modifying the existing MOSFET technologies, recent new technologies are considered as future and as per prediction of the Global Market for carbon nanotubes report, CNTFET is going to make a severe impact in the semiconductor market. In this paper, first AC analysis is done by varying number of channels of GAA-CNTFET of Common Source Amplifier and results are shown in the form of a graph. Then AC analysis is performed by varying diameter of GAACNTFET and from the result of this analysis which maximum gain was obtained is chosen. Similarly, AC analysis is formed by varying oxide thickness (tox) and dielectric material (kox) and from the results of these analyses, the best-case gain is obtained for single stage, two stages, and three stages common source amplifier using CNTFET on 11 nm technology. In the frequency domain, it corresponds to 19.102 dB for single stage, 38.26 dB for two-stages and 56.34 dB for three stages. © 2020 IEEE.