Operating characteristics of a clamp klystron oscillator at E-band

Abstract

We describe a klystron-like oscillator operating at a frequency of 77.2 GHz (E-band) using particle-in-cell (PIC) simulations with the code MAGIC. It is shown that the klystron oscillator with one “buncher” cavity and one “catcher cavity” shaped like a “clamp” driven with an applied voltage U=20 kV−100 kV can operate with an electronic efficiency of above 11% with MW output power. To increase the electronic efficiency, we combined two clamp klystrons along the z-axis in a hybrid configuration between a klystron and the slow wave structure of a coupled-cavity TWT. PIC simulations demonstrate that when this hybrid design operates in the TE30 mode, its electronic efficiency can be as high as 28% with an output power as high as 1.35 MW. This article describes in detail this approach to the high power millimeter-wave source design.