UCD gyro-TWT program: 94-GHz TE/sub 01/ gyro-TWT and 44-GHz third-harmonic slotted gyro-TWT

Summary form only given. Two high performance gyro-TWT amplifiers are being constructed at UCD. A high power CW-capable gyro-TWT operating in the low-loss TE/sub 01/ mode will be driven by a 100 kV, 5 A, v/sub /spl perp///v/sub Z/=1.0 MIG electron beam with /spl Delta/v/sub Z//v/sub Z/=5%. The three-stage amplifier is predicted by our large-signal simulation code to generate 105 kW at 94 GHz with 21% efficiency, 45 dB saturated gain and 5% constant-drive bandwidth. Linear theory has been used to determine the threshold start-oscillation beam current for absolute instability and the critical section lengths for the potential harmonic gyro-BWO interactions. A novel, lossy mode-selective circuit is being considered for increasing the section lengths in order to remove one sever and further increase the efficiency. In addition, a third-harmonic gyro-TWT amplifier will be tested at 44 GHz. A slotted interaction circuit is utilized to achieve strong amplification near the third cyclotron harmonic frequency.