A wideband fundamental mode millimeter gyrotron TWA experiment

The tapered wall gyrotron traveling-wave amplifier (gyro-TWA) has promise to be a wideband high power millimeter wave amplifier. The present experiment is a reflection amplifier and is designed to have 38% bandwidth at a 33.5 GHz center frequency. The circuit is a fundamental mode TE^□10linear tapered rectangular waveguide 50 cm long. The magnetic field is profiled to maintain synchronism with a series of twenty individually adjustable coils. The beam is formed by a novel type of space charge limited gun in which a Pierce gun beam is injected into an electrostatic kicker system to impart transverse energy. Calculation results of an active circulator gyro-TWA which provides a method of simple signal injection into the tapered circuit are presented.