Characteristics of a stable 200 kW second-harmonic gyro-TWT amplifier

The experimental results are reported for a stable second-harmonic gyrotron traveling-wave amplifier, which generated a record breaking 207 kW output power based on the principle that the weaker harmonic interactions are more stable to spontaneous oscillations than the fundamental, and therefore, more capable of generating higher output power. The Ku-band amplifier utilized an 80 kV, 20 A, v/sub /spl perp///v/sub /spl par//=1.1 MIG electron beam and displayed an efficiency of 12.9%, an output phase variation of 10/spl deg//kV, a saturated bandwidth of 2.1%, a large-signal gain of 16 dB, a detuned small-signal gain of 38 dB, and was completely (zero-drive) stable.