A K-Band CMOS Power Amplifier using an Analog Predistortion Linearizer with 22.1 dBm Psat and 0.9° AM-PM Distortion

This paper presents a K-band analog predistortion linearized CMOS power amplifier (PA) using a variable inductor and cold-FET. Unlike conventional cold-FET linearizers, which face limitations in improving amplitude-to-phase (AM-PM) distortion at high output power, the proposed linearizer compensates both AM-PM distortion and amplitude-to-amplitude (AM-AM) distortion of the PA. Especially, the proposed linearizer has a phase-lag characteristic at medium output power and seamlessly transitions to a phase-lead characteristic at high output power, which compensates for AM-PM distortion of the PA up to high output power. The implemented PA achieved a peak power-added efficiency of 34.4%, saturation output power of 22.1 dBm, and P1dB of 19.44 dBm. Also, AM-PM distortion of only 0.9° was achieved throuth the proposed linearization technique, allowing the PA to achieve the highest linear output power of 14.9 dBm while satisfying EVM values of -30 dB among the recently reported K-band CMOS PAs.