Results of a wideband 2nd harmonic gyro-amplifier (phigtron) experiment

Summary form only given. A new member of gyrotron family, a "phase coherent, harmonic-multiplying, inverted gyrotwystron" (phigtron) has been experimentally characterized operating as a high performance, powerful millimeter wave amplifier. This novel device consists of a gyro-TWT as the prebunching input section operating at the fundamental cyclotron resonance and a two cavity, second harmonic output section. Operating parameters were optimized. Frequency doubled peak power of 430 KW was achieved in the TE/sub 03/ mode with an /spl ap/0.85% bandwidth, 35 dB gain, 0.026 degree per volt phase fluctuation (due to beam voltage variation), and 32% efficiency at center frequency of 33.4 GHz. This measured performance considerably advance the state-of-the-art for millimeter wave gyrotron amplifiers. A upgraded design of the phigtron using a new extended interaction cavity (EIC) as an output section is also presented.