W-band harmonic multiplying gyrotron traveling-wave amplifier

This study proposes a W-band harmonic multiplying gyro-TWT operating at lower-order modes to avoid the fundamental harmonic absolute instabilities. The W-band harmonic multiplying gyro-TWT is predicted to yield a peak output power of 100 kW at 98 GHz with an efficiency of 22.5 %, a saturated gain of 24 dB and a 3 dB bandwidth of 1.1 GHz for a 60kV, 7.42 A electron beam with an axial velocity spread of Δv
_z
/v
_z
=8%.