Experimental studies of bandwidth and power production in a three-cavity, 35 GHz gyroklystron amplifier

The operating characteristics of a three-cavity, Ka-Band gyroklystron emplo ying a large amount of stagger-tuning are reported. Particular attention is given to examining how the frequency response (peak power, bandwidth, and overall shape) is altered by changes in operating parameters. A peak power of 225 kW at 34.90 GHz, with a 2 mu s pulse length, 32% efficiency, 30.3 dB saturated gain, and a 3 dB bandwidth of 0.82% (286 MHz) was obtained with a 70.2 kV, 10.0 A beam at a magnetic field of 13.07 kG. This operating poin t represents a compromise between the output power and the bandwidth. The o perating magnetic field was found to have a dramatic influence on the power -bandwidth tradeoff; a lower field of 12.91 kG produced 245 kW with 0.63% b andwidth, while a higher field of 13.39 kG increased the bandwidth to 0.94% at a lower power of 200 kW. The results are in excellent agreement with la rge signal simulations. (C) 1999 American Institute of Physics. [S1070-664X (99)02001-7].