5.4 A 22nm FDSOI CMOS-Based Compact 3-Stack Doherty Power Amplifier with a Stacked OPA-Based Bias Scheme Achieving >16.5dBm Pavg for 5G FR2 Applications

The increasing demand for wireless communication has generated significant interest in the millimeter-wave (mm-wave) band. In this frequency range, phased-array systems are crucial for sustaining communication performance despite high propagation loss. In highly integrated phased-array systems, multiple power amplifiers (PAs) need to be integrated within a transceiver chip, requiring compact PA designs. As a result, silicon-based CMOS technology offers benefits in terms of miniaturization and integration, making it appropriate for phased-array-system PAs. Meanwhile, emerging applications, such as fixed wireless access (FWA), require an equivalent isotropic radiated power (EIRP) of over 70dBm, necessitating an increase in PA output power. Moreover, 5G new-radio (NR) orthogonal-frequency-division-multiplexing (OFDM) systems exhibit peak-to-average power ratios (PAPRs) exceeding 10dB, demanding substantial back-off in PA operations to avoid signal distortion. These challenges highlight the importance of Doherty PA structures, which can maintain relatively high power-added efficiencies (PAEs) even during back-off. Designing compact, high-output-power, and efficient Doherty PAs remains a challenge but is very crucial for addressing the demands of modern wireless communication systems.