Design of a RF Doherty Power Amplifier Based on Handset Application

A Doherty Power Amplifier (PA) with high efficiency and high linearity that can be used in smart communication devices such as mobile phones in the sub-6GHz frequency band is proposed. This Doherty PA uses the InGaP/GaAs hetero-junction bipolar transistor (HBT) process. Compared with the traditional Doherty PA, the PA in this paper combines the choke inductance of the output collector and the phase compensation circuit with the output circuit of the Doherty PA respectively, which reduces the number of components required for matching. From the simulation, when the power supply voltage of the Doherty power amplifier is 4.2V, the operating frequency is 3.5GHz and the output power is 26.5dBm, the power added efficiency (PAE) reaches 34.5%, at the same time when using a 10MHz bandwidth LTE-3GPPFDD modulated signal the Adjacent Channel Power Ratio (ACPR) below to -35dBc.