Single-stage f.e.t. amplifiers operating in K-band have been constructed using the Varian VSX 9305 0.5 μm-gate GaAs f.e.t. An amplifier gain of 9±1 dB was obtained over the frequency band 18.5–20.5 GHz and gain of 8±1 dB was observed from 23.0 to 26.0 GHz. An amplifier noise figure of 5.6 dB was measured at 24 GHz.