A low-noise amplifier (LNA) at Ku-band with variable gain for adaptiveantenna combining is presented. The compact MMIC is optimized forlow-power-consuming wireless local area network applications andis fabricated using commercial 0.25-/spl mu/m bipolar complementarymetal-oxide semiconductor technology. At 16 GHz, a supply voltageof 1.5 V and a current consumption of only 1.5 mA, maximum gain of14.5 dB, noise figure of 3.8 dB, and third-order intercept pointat the output of 1 dBm are measured. At a supply voltage of only1 V and a supply current of 0.9 mA, a gain of 11 dB was achieved,yielding a gain per supply power figure-of-merit of 12.2 dB/mW, which,to the knowledge of the authors, is the highest reported to datefor Ku-band LNAs, independent of the technology used. The characteristicsof different bias methods for amplitude control of the cascode circuitare elaborately discussed. A bias-control method is proposed to significantlydecrease the transmission phase variations versus gain.