The frequency agility of a W-band gyrotron travelling wave amplifier (gyro-TWA) was demonstrated by the amplification of a frequency-swept input signal (chirp signal). The gyro-TWA was developed to provide high output power and wide bandwidth by using a helically corrugated interaction region. In the experiment a ~0.5 W signal of linearly swept frequency bandwidth of 1 GHz was amplified and a gain of over 30 dB was measured when driven by a 40 keV, 1.5 A, axis-encircling electron beam
