A Wideband Low-Power CMOS LNA With Positive–Negative Feedback for Noise, Gain, and Linearity Optimization

A wideband common-gate (CG) low-noise amplifier (LNA) utilizing positive-negative-feedback technique is presented. The positive-negative-feedback technique boosts effective transconductance (
G
_m
) and output impedance, which leads to an LNA with higher gain and lower noise figure (NF) over the previously reported amplifiers. In addition, this approach provides high linearity with an aid of third harmonic cancellation, and it breaks transconductance (
g
_m
) constriction for input matching in CG amplifiers. In this paper, linearity and output impedance improvement through the proposed technique are fully analyzed. An LNA prototype is implemented in 0.18- μm CMOS technology occupying a total area of 0.33 mm
²
. The implemented LNA delivers a maximum voltage gain of 21 dB, a minimum NF of 2 dB, an third-order intermodulation intercept point of -3.2 dBm, and 3.6 mW of power consumption in 300-920 MHz of 3-dB bandwidth with input matching (
S
₁₁
<; -10 dB).