Novel linearization technique is proposed to realize a linear CMOS power amplifier IC for 5-GHz band WLAN applications. A CMOS power amplifier IC is designed, fabricated and fully tested using TSMC 130-nm CMOS technology. With the proposed techniques, the measurement results show a third-order IMD improvement of 9 dB over wide output power range and the maximum improvement of 18 dB. The power amplifier IC exhibits an output P1dB of 19.5 dBm and a power gain of 9.5 dB at an operation voltage of 3.3 V.