An Area and Power Efficient Cartesian Phase Shifter + Mixer Circuit Applied to WLAN System

A two-antenna array receiver is designed for WLAN application to build a maximum ratio combiner (MRC) system. A new signal-path Cartesian phase generation and combination technique is proposed to shift the RF signal by 22.5 phase steps. The 3 dB improvement in received SNR is achieved in comparison to single path receiver. The 0.29 mm^2 RF paths consumes 30 mW in 0.13 mum CMOS process.