A 2.4-GHz fully-differential RF front-end on 0.18-mum CMOS technology for wireless sensor network (WSN) applications consuming 4.8-mW from a 1.8-V supply is presented. The direct conversion RF-front end comprises of low-noise amplifier (LNA), I/Q direct-conversion mixers, quadrature LO generator and LO buffers. By employing conventional source degenerated LNA, passive mixer, to eliminate flicker noise, RC poly-phase filter for quadrature LO generation, and LO buffers employing current reuse technique, we achieve 23-dB conversion gain, 8.1-dB noise figure, -15-dBm IIP3 and better than 15-dB input return loss for the RF front-end