Experimental study on harmonic-multiplying two-stage tapered gyro-TWT

A Ka-band harmonic-multiplying gyro-TWT has been designed using a self-consistent nonlinear theory and the experimental work is underway. A saturated gain of 23 dB, a bandwidth of 3%, and an efficiency of 10% were predicted when a 30 kV, 1 A cusp gun was employed with axial velocity spread of 4%. The preliminary experimental results will be presented along with the cusp gun, magnetic field measurement, a directional coupler.