A K-band compact fully integrated transformer power amplifier in 0.18-μm CMOS

A K-band, 24 GHz, fully integrated transformer power amplifier (PA) is designed and fabricated in the standard 0.18-μm deep N-well (DNW) CMOS technology. This power amplifier is a 2-stage design using cascode RF NMOS configuration. The on-chip transformers are adopted for the power combining and impedance transformation for the matching network with a small size. The measurement results of this PA are linear gain of 15 dB, OP_1dB of 18 dBm and P_SAT of 23.5 dBm with power added efficiency (PAE) of 12%. Due to the small size of transformer, the size of the chip is only 0.86 × 0.56 mm². To the author´s knowledge, this PA not only demonstrates the highest output power among the CMOS PA in a 0.18-μm CMOS process, but also achieves the highest ratio of output power to chip size among the all reported K-band CMOS PAs.