High-power 10%-tuning-bandwidth varactor-controlled impatt oscillator/amplifier

A simple electronically tuned c.w. GaAs impatt/varactordiode oscillator/amplifier circuit is described which can be tuned over a 10% bandwidth at mid-X-band frequencies at a power level greater than 0.5 W as an oscillator, and greater than 0.8 W at the 6 dB-gain level as a reflection amplifier. Unambiguous electronic tuning without power jumps, frequency hops or `out-of-band? oscillations has been achieved by paying special attention to the circuit design.