A 3.5 GHz CMOS Doherty power amplifier with integrated diode linearizer targeted for WiMax applications

In this work, a novel integrated Doherty power amplifier in 0.18 mum CMOS process is presented for potential WiMax applications at 3.5 GHz. Doherty configuration with cascode transistors is adopted to achieve high efficiency and output power. The integrated diode linearizer is first demonstrated to use on the cascode transistor to improve the linearity of Doherty PA. The proposed power amplifier provides a maximum output power of 24.44 dBm and a power added efficiency (PAE) as high as 43% at 3.5 GHz operation frequency. At 1-dB compression point this PA exhibits 23.63 dBm of output power with 36.1% PAE. The third order inter-modulation (IMD3) comparison obtained from two-tone test, reveals the linearity improvement from the diode linearizer. Layout and corner simulations results are also included.