In this paper, a 3.1-10.6 GHz fully integrated lowpower CMOS direct-conversion receiver for ultra-wideband (UWB) applications is proposed and analyzed. The proposed receiver consists of a wideband low-noise amplifier (WLNA), quadrature down-conversion mixers, output I/Q buffers and a carrier generator. This chip was designed in 0.13-um CMOS technology. According to the simulation results, the proposed receiver has noise figure (NF) of 4.1-7.1 dB, receiver voltage gain of -22-dB, and input-referred 1-dB compression point (P1dB) of -22-26 dBm and third-order intercept point (IIP 3) of -12-16 dBm. It consumes 38.4 mW from 1.2 V power supply.