60 GHz and 80 GHz-band power amplifier (PA) MMICs have been developed on a standard 90nm CMOS technology for use in RF front-ends of wide-band, low-cost communication and/or radar systems. A 60 GHz three-stage PA and a 80 GHz five-stage PA, both with single-ended architecture, have demonstrated saturated output powers of 12.6 dBm and 10.3 dBm with linear gains of 10.0 dB and 12.2 dB, respectively, the highest Psat's reported to our best knowledge, under a 1.0 V power supply voltage. The PA's were designed with systematically shifted cut-off frequencies of individual high-pass-type matching circuits to simultaneously achieve wide-band operations, resulting in demonstrated 1dB-gain bandwidth of 17 GHz (55 GHz to 72 GHz), and 19 GHz (66 GHz to 85 GHz), respectively.