Broadband operation of a gyro-TWT with a dielectric loaded waveguide is demonstrated. Fast wave interaction allows the beam quality requirements to be reduced. Self-consistent nonlinear simulation has been performed and shows that an instantaneous bandwidth of 20% with a moderate efficiency of 13% can be achieved by using a low a beam with a 2% axial velocity spread. Parameters for a proposed Ka-band amplifier are given.
K. C. Leou,
"Dielectric loaded wideband gyro-TWT", Proc. SPIE 1514, 15th International Conference on Infrared and Millimeter Waves, 15146C (1 December 1990); doi: 10.1117/12.2301638; https://doi.org/10.1117/12.2301638