In this paper, a novel low-complexity RF front-end circuit for IR-UWB receiver based on non-coherent communication was presented. The RF front-end includes a wideband low noise amplifier (LNA), a correlator, an integrator and a comparator. The RF front-end circuit operating under 1.8V is implemented in a 0.18-μm CMOS technology. The wideband input impedance matching of LNA is conducted by employing an RC feedback network and a degenerating inductor. A Gilbert mixer is used as the correlator. A current injection technology is used to improve the gain and linearity of the mixer. The simulation results show that: the noise figure (NF) of the LNA is from 2.6 to 3.1 dB and the reflected coefficient is with S11 < -10 dB, covering standard UWB bandwidth of 3~5 GHz. The average power gain of LNA is about 16.8 dB. The mixer gets a conversion gain of 15.01 dB and its IIP3 is -3.47 dBm. The designed receiver front-end can correctly demodulate IR-UWB signals with a data rate of 50Mbps under a power of
-90dBm.