A 28-GHz CMOS Power Amplifier With Adaptive Bias and Phase Compensation for Gain and Phase Linearity Enhancement

This brief presents a 28-GHz PA fabricated in the TSMC 90-nm CMOS process for 5G wireless communication phased-array transmitters. The proposed PA incorporates adaptive bias and phase compensation techniques to effectively mitigate AM-AM and AM-PM distortions, achieving high linearity and efficiency. The design features an envelope detector for dynamic bias adjustment, enhancing transconductance to reduce AM-AM distortion. Furthermore, a varactor-based phase correction mechanism is implemented to minimize AM-PM distortion. This brief improves both gain and phase control networks, resulting in significant improvements in key performance metrics, including $OP_{1dB}$ , $PAE_{P1dB}$ , and maximum phase distortion before $P_{1dB}$ . The proposed PA achieves an $OP_{1dB}$ of 14.4 dBm, a $PAE_{P1dB}$ of 33.6%, and a maximum AM-PM distortion of 1.5°, demonstrating exceptional performance and scalability for phased-array applications in next-generation millimeter-wave systems.