A K-Band CMOS High-gain Power Amplifier Using Transformer-feedback Cascode Topology

The paper presents a K-band high-gain power amplifier (PA) using transformer-feedback cascode topology, implemented in a 0.18-μm CMOS process. Due to the tradeoff between high gain and wide operational bandwidth, different coupling coefficients of the two transformers are addressed. The proposed high-gain PA demonstrated a measured maximum small-signal gain of 18.6 dB, with a 3-dB bandwidth from 20 to 26.1 GHz, corresponding to a fractional bandwidth of 26.5%. The measured output 1-dB compression point (P<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1dB</inf>) is 11.7 dBm. Furthermore, the proposed PA also achieves a measured output third-intercept point (OIP3) of 26.7 dBm. The measured dc power consumption is 216 mW with a supply voltage of 3.6 V. The chip size of the proposed high-gain PA is 0.53 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>. This work is highly suitable for certain millimeter-wave applications due to its high-gain characteristic.