A Concurrent Dual-Band Low-Noise Amplifier With Active Feedback and Self-Biasing for WLAN

This letter presents an asymmetric concurrent dual-band low-noise amplifier (CDB-LNA) designed for wireless local area network (WLAN) applications requiring different bandwidths: a 2.4-GHz narrowband and a 5.1–7.1-GHz broadband. Based on a cascode core with a self-biasing technique for single-supply operation, the design employs a gate–source connected lightly doped feedback (LDF) transistor instead of a traditional resistor in the resistor-inductor-capacitor (RLC) feedback to achieve a better noise figure (NF). Dual-band matching networks are utilized for both noise and gain. Fabricated in a 0.15-$\mu $m D-Mode gallium arsenide pseudomorphic high electron mobility transistor (GaAs pHEMT) process, the measured results show that across the 2.3–2.5-GHz and 5.1–7.1-GHz bands, the amplifier achieves NFs of 1.4/1.4dB, gains ($\vert S 21\vert $) of 14.3/13.9 dB, and input/output return losses ($\vert S 11\vert $/$\vert S 22\vert $) better than −17.2/−14.1 dB, respectively. The chip area, including pads, is$1200\times 580$$\mu $m2.