2017 Volume 14 Issue 22 Pages 20170985
This paper presents a multiband reconfigurable low noise amplifier (LNA) based on dual-feedback common-gate (CG) configuration. The input impedance of the LNA is tuned synchronously with output load due to the reflection of load impedance to input by the proposed source-follower positive feedback method. This method also improves the stability of the LNA, which is an issue in conventional positive feedback methods. In addition, both the source-follower positive feedback and the negative feedback by capacitor cross-coupling help to reduce noise figure. Fabricated in TSMC 0.18 µm CMOS process, measurement results show the LNA is reconfigurable from 1.833 GHz to 2.47 GHz, with S11 automatically centered with S21. It achieves a power gain from 15 to 17.4 dB, 1.62 dB minimum NF, and −4.4 dBm maximum IIP3. 10.5 mA current is consumed from 1.8 V supply.
