Abstract:A highly efficient and linear Doherty Power Amplifier(PA) which operates at 3.5 GHz World Interoperability for Microwave Access(WiMAX) band is designed. To maintain high linearity and high efficiency of the Doherty PA, a technique adjusting the baseband and harmonic impedances appropriately is applied to the carrier cell, and nonlinearity cancellation between the carrier PA and the peaking one is also utilized. The simulation results show that using the appropriate gate bias of the peaking amplifier, the proposed Doherty power amplifier can achieve the Power-Added Efficiency(PAE) as high as 63%, while the third-order Inter-Modulation Distortion(IMD3) and the fifth-order Inter-Modulation Distortion(IMD5) are less than -30 dBc.