Design of a Multi-Stage Common Source LNA with Enhanced Gain and Noise Performance for SIGINT Applications

This paper proposes a multi-stage common-source Low Noise Amplifier(LNA) that achieves high gain and superior energy efficiency, utilizing 90 nm CMOS technology. The application of LNA in SIGINT systems has drawn significant interest due to its effectiveness in amplifying weak signals while minimizing external noise. Achieving a low noise figure while preserving low power consumption is a major challenge in LNA design for portable systems. With a supply voltage of 1.2 V, the proposed LNA achieves a noise figure ($\boldsymbol{N} \boldsymbol{F}_{\text {min}}$) of 6.21 dB and a power gain of 34.43 dB over the frequency range of 7.069 GHz to 7.4558 GHz. It ensures the maximum output power transmission to a 50Ω load by having a strong impedance matching of $S_{11}<$ -11.907 dB and $S_{22}<-9.04 \text{dB}$. At the operating frequency of 7.243 GHz, the S-Parameters are $S_{11}=-12.43 \text{dB}, S_{22}=-15.11$ dB, and $S_{12}=-88.9885 \text{dB}$, and the power consumption is 69.33 mW. The LNA is stable as $K f>1$ and $B 1 f>0$, which meets the desired specifications.