An integrated switchable cascode RF power amplifier in GaN technology

In this paper an integrated switchable cascode RF power amplifier (PA) will be presented. Modern communication standards use coding schemes with high peak to average power ratios (PAPR) therefore PA efficiency in back off is key to efficient transmitters. The proposed switchable cascode PA, which is based on a modified cascode structure, is capable of providing such an efficiency peak in back off. The operational principle is explained and a possible circuit implementation in GaN technology at 2.65 GHz is presented. At a maximum power of 2.74 W the circuit has a power added efficiency (PAE) of 65.4 % and at 0.57 W (6.7 dB backoff) a PAE of 60.2 %. In addition the combination with other efficiency enhancement methods such as baseband PWM or direct filter connection are covered.