A 0.18-$muhbox m$CMOS Selective Receiver Front-End for UWB Applications

This paper addresses the problem of 5–6-GHz WLAN interferer rejection in a direct-conversion receiver front-end for multi-band orthogonal frequency division multiplexing (OFDM) ultra-wideband (UWB) applications. The IC, realized in a 0.18-$muhbox m$CMOS technology, comprises a single-ended voltage–voltage feedback low-noise amplifier (LNA) and a quadrature mixer. The LNA employs a double-peak single-notch network in the output load, amplifying UWB groups #1 and #3, while rejecting WLAN interferes in the 5–6-GHz frequency range. The mixer, based on a merged quadrature topology, also realizes a second-order low-pass filtering. Fabricated dies have been bonded on PCB for characterization. The front-end, drawing 10 mA from 1.8 V, achieves a 1-dB gain desensitization with a$-$6.5-dBm interferer power at 5.5 GHz. Other measured performances are 5.2-dB and 7.7-dB minimum and maximum noise figure (NF),$-$3.5-dBm minimum IIP3 and$+$34.5-dBm minimum in-band IIP2 and$+$21-dBm out-of-band IIP2.