In this paper, we designed the high linearity power amplifiers that applying 2.4 GHz WLAN and 3.5 GHz WiMAX systems by monolithic microwave integrated circuit (MMIC) technology. The power amplifiers are implemented with TSMC 0.18 um CMOS and WIN 0.15 pHEMT processes. The power amplifiers employ class-AB topology to overcome the low efficiency when high linearity operated, and using linearizer in the PAs to maintain the high linearity. And we propose a modified circuit to complement the phase deviation of the CMOS cascade topology that could improve the linearity of the power amplifier.