A 26 GHz GaN-MMIC with Integrated Switches for Discrete Level Supply Modulation

A GaN-MMIC power amplifier (PA) for 5G applications in the 24 - 28 GHz frequency range with integrated multi-supply switches is presented. It is a three-stage conceptual design developed for the investigation of multi-stage discrete level supply modulated systems (class-G). The MMIC that was fabricated in the FBH 150 nm GaN-HEMT process includes reconfigurable power-supplies for two PA stages where the middle stage can be boosted with a high-level drain supply and the final-stage PA allows 3 levels of drain supply. The investigated amplifier shows 1.9 W peak output power at 26.4 GHz and a maximum PAE of 18.5%. A quasi-static evaluation shows a possible efficiency improvement of 5%-points at 5dB output power back-off including static losses in the switches. The integrated planar diodes in the class-G switches show a forward voltage drop of more than 1.5 V severely reducing the performance at low-voltage operation.