Three-Stacked CMOS Power Amplifier to Increase Output Power With Stability Enhancement for mm-Wave Beamforming Systems

In this study, an mm-wave band complementary metal–oxide–semiconductor (CMOS) power amplifier (PA) with a two-stage differential structure was designed. An analysis of the designed PA is presented and a new structure is proposed to eliminate the possibility of oscillation in the PA, which has high gain and high output power. The designed driver stage consists of a pair of cascode amplifiers and can be advantageously applied in beamforming systems as the PA phase is converted to 0°/180° with the ON/OFF of a common-gate (CG) bias voltage. The power stage was designed with a three-stacked structure to obtain a high output power. The stability was improved using RC and capacitive feedbacks in the power stage. We implemented the PA using the 65-nm RF CMOS process. The designed PA used supply voltages of 2.0 and 3.3 V for the driver and power stages, respectively, and its saturated output power was measured as 24.7 dBm at 22.0 GHz. In this case,
$\text{P}_{\mathrm {1\,dB}}$
was 20.6 dBm and the peak power added efficiency (PAE) was 26.0%.