A 2.4 GHz CMOS Low-IF Receiver Front-End for WLAN Applications

Abstract

A CMOS low-IF receiver front-end applied for Wireless Local Area Networks (WLANs) is presented in this paper. The receiver front-end comprises a low noise amplifier (LNA), a down-converter, a single-to-fully converter, a polyphase filter, and a summator/subtractor. This low-IF architecture achieves 0.46° phase error and 0.7 dB gain mismatch in i>I–i>Q channels while the 2.4 GHz RF signal is down-converted into 100 MHz of IF band. The cascaded noise figure (NF) of LNA and polyphase network is 4.89 dB within the WLANs' requirement. The chip realized in a 0.6 μm CMOS technology occupys 2.4 mm × 2.1 mm active area. From a single 3.3 V power supply, it consumes 300 mW power.