A fully integrated low power transmitter for an IEEE 802. llb transceiver system is implemented in SMIC 0.18μm technology. The direct-conversion transmitter includes two Chebyshev I low pass filters,two PGAs,a SSB mixer, and a PA driver. The transmitter provides a gain control of 32dB in 3dB steps. The maximum output power is - 3.4dBm and the EVM is 6. 8%. The power consumption of the transmitter is only 57.6mW with a 1.8V power supply. The chip area of the transmitter is 1.6mm × 1.6mm.