Design and performance of traveling-wave tubes using field emitter array cathodes

An X-band miniaturized traveling-wave tube TWT.using a Spindt field emitter array FEA.cathode was built. The FEA cathode has 542,000 molybdenum tips in an emission area 1.2 mm in diameter. It also has a trench current-limiter that shows low resistance in normal operation. A saturation output power of 28.2 W, a saturation power gain of 40 dB, and a beam transmission ratio of more than 99.3% have been achieved at a frequency of 11.5 GHz under 3% duty ratio. q1999 Elsevier Science B.V. All rights reserved.