A 1.2V, 1.8 GHz CMOS two-stage LNA with common-gate amplifier as an input stage

This paper presents a 1.2V CMOS 2-stage low-noise amplifier (LNA) operating at 1.8 GHz. The amplifier can provide a power gain of 17.4 dB with a low noise figure of about 1 dB. The input and output reflection coefficient (S₁₁ and S₂₂) are -6.4 and -31.8 dB, respectively. In this circuit, common-gate amplifier with noise matching is employed as the input stage to achieve this low noise figure. Moreover, inter-stage matching technique is introduced in the design to give enough power gain for signal amplification.