A Current-Equalized Distributed Receiver Front-End for UWB Direct Conversion Receivers

This paper presents a current-equalized distributed RF front-end for ultra-wideband (UWB) direct conversion receivers. The proposed distributed direct conversion RF front-end (DDC-RF) utilizes a current equalization technique to remove the systematic IQ phase and gain imbalances imposed by the intrinsic wideband characteristics of the distributed circuits. Fabricated in a 0.13 mum CMOS process, the proposed DDC-RF prototype achieves 12.1-13.4 dB gain and an average noise-figure (NF) of 6.8 dB across the UWB frequency band with 50 Omega wideband-matched termination. A programmable RF termination allows the DDC-RF to achieve higher gain of 16.5 dB and lower NF of 4.3 dB, while trading off with few decibels of mismatch at the RF input port. The measured IQ gain and phase imbalances are less than plusmn0.5 dB and plusmn2.5deg, respectively. The 2-stage DDC-RF consumes 8 mA from 1.8 V supply voltage, and occupies an area of 1.2 mm².