Fully Integrated HBT MMIC Series-Type Extended Doherty Amplifier for W-CDMA Handset Applications

Abstract

A highly efficient linear and compactly integrated series-type Doherty power amplifier (PA) has been developed for wideband code-division multiple access handset applications. To overcome the size limit of a typical Doherty amplifier all circuit elements, such as matching circuits and impedance transformers, am fully integrated into a single monolithic microwave integrated circuit WC). The implemented PA shows a very low idle current of 25 mA and an excellent power added efficiency of 25.1% at an output power of 19 dBm by using an e-wended Doherty concept. Accordingly, its average current consumption was reduced by 51% and 41% in urban and suburban envinonments, respectively when compared with a class-AB PA. By adding a simple predistorter to the PA, the PA showed an adjacent channel leakage ratio better than -42 dBc over the whole output power range.