A 402 ∼614 MHz CMOS transceiver is proposed and designed in standard 0.18$\mu$m CMOS technology, complying with the IEEE 802.15.6 Wireless Body Area Network (WBAN) standard. A current-reused differential common-gate low noise amplifier (CG-LNA), a high precision image rejection active-RC complex filter, a four-stage programmable gain amplifier (PGA), a high linearity power amplifier (PA) and so on, are employed. The simulation results show that, within the desired bandwidth from 402 MHz to 614MHz, the input/output power reflection coefficients of less than -16dB, the receiver gain range of $38 \sim 87$ dB and the output 1 dB compression point of over 2.11dBm are achieved. From a single voltage supply of 1.8V, 8mW and 16mW are consumed by the receiver and the transmitter, respectively.