Studies of the effect from reflection with a short-pulse high-power gyrotron

The effect of reflection is studied experimentally on a 110 GHz, 1.2 MW short-pulse gyrotron. The experimental setup allows variation of the reflection from 0 to 35% over a range of gyrotron operating conditions. For high-efficiency operating points, the reflection is causing a decrease of the gyrotron power and is responsible for the excitation of an unwanted transverse mode, suppressing the excitation of the main mode.