I. Introduction
The millimeter-wave (mm-wave) spectrum is suitable for high-data rate applications, such as 5G wireless communication, satellite and mm-wave radar. The demand for wirless connectivity on high-speed cellular devices drives 5G mm-wave new radio (NR) specifications from 24-to-43 GHz [1]. Beamforming-based MIMO receivers are usually required to meet the mm-wave link budget. Power amplifier (PA) is one of the most critical building blocks among those receivers. It is expected to provide sufficient output power (around 18-to-24 dBm) with enough efficiency (> 20%) across the frequency range of interest [2].