Dual mode broad bandwidth high efficiency traveling-wave tube

The development of a 10 dB pulse-up periodic permanent magnet focused high efficiency traveling-wave tube is described and experimental data is presented, Peak power levels of 4600 Watts were attained in the high power pulse mode of operator. Continuous wave power levels of 600 Watts have been demonstrated. Efficiencies up to 47 percent in the pulse mode and 38 percent in the CW mode were achieved. The objective was to obtain both a high average power capability and high efficiency at differing output power levels. A dual mode electron gun was designed and evaluated. Favorable beam characteristics were demonstrated at different perveance levels. Experimental test results shown excellent beam transmission. Shield loading techniques were used to reduce phase velocity dispersion. A helix phase velocity taper was used to improve basic interaction efficiencies. A three-stage, double depressed, collector was added to further improve overall conversion efficiency. Experimental data taken in C-band are presented. The performance of the device represents an advance in the state of the art of high efficiency, high average power, 10 dB pulse up, dual mode traveling-wave tubes.