EXPERIMENTAL INVESTIGATION OF A BROAD-BAND DIELECTRIC-LOADED GYRO-TWTAMPLIFIER

The bandwidth of a gyrotron travelling wave amplifier has been broaden ed by incorporating a dielectric-loaded interaction waveguide to reduc e the circuit's dispersion. This proof-of-principle experiment was des igned for the X-band frequency range and operates in the fundamental m ode of a rectangular waveguide loaded with dielectric Macer. The ampli fier is zero-drive stable and demonstrates a peak output power of 55 k W, 11% efficiency, 27 dB saturated gain with an unprecedented untapere d gyro-TWT constant-drive bandwidth of 11% and a saturated bandwidth o f 14%. Its performance can be further enhanced by reducing the beam's axial velocity spread as shown by previous simulation studies.