A 60-GHz 1.2 V 21 dBm power amplifier with a fully symmetrical 8-way transformer power combiner in 90 nm CMOS

A 60-GHz 1.2 V power amplifier (PA) using fully symmetrical 8-way transformer power combiner is designed in 90 nm CMOS. The fully symmetrical transformer power combiner structure mitigates the impedance imbalance caused by uneven voltage coupling between primaries and secondary. At 60 GHz, impedance uniformity between four input ports of the transformer power combiner is better than 5% in real part and 7% in imaginary part. Loss of the transformer power combiner is 1 dB. At 60 GHz, small signal gain of the PA is 16.8 dB. 1-dB gain compression point output power is 17.2 dBm. Peak power-added efficiency (PAE) and saturated output power are 13.4% and 21 dBm.