A 2.4 GHz, 1 dB noise figure common-gate LNA for WLAN frontend

In this work, a low noise figure, high linearity cross-coupled negative feedback common gate (CG) low noise amplifier (LNA) in 1.2 V, 65 nm CMOS technology with a unique output conductance optimization method is proposed. Traditionally, CG-LNAs are known for their good linearity at the cost of a poor noise figure, making them limited to few applications where high linearity is the primary goal. The proposed CG-LNA achieves a low noise figure (NF) of 1 dB and high linearity (IIP3) of +1.41 dBm. This is achieved by a novel design optimization method by using the output conductance (g
_ds
) of the frontend CG-LNA to break the deadlock among NF, S11 and S21 optimization in the traditional CG-LNA design methodology. This g
_ds
based optimization approach simultaneously achieves low noise figure and high linearity while meeting the other critical LNA specifications. Proposed CG-LNA performance shows a simulated S21 of 23dB at an S11 of -13.5dB while operating at the 2.4 GHz IEEE 802.11g WLAN band. The proposed CG-LNA occupies an active area of 0.38 mm
²
while consuming power of 54 mW.