GaAs field-effect transistors with a Schottky-barrier gate have been investigated in the frequency range 12–20 GHz. Measurements of the maximum available gain have shown that the devices have much higher gain in this range than has been expected. A 17 GHz oscillator having an output power of 4mW and a 4-stage 14.9GHz amplifier with 16 dB of power gain have been built using stripline technique.