Research on Sub-Microsecond Compact L-Band Relativistic Cherenkov Oscillator

Prolonging the microwave pulsewidth is an important research direction to improve high-power microwaves’ energy and average power level. In this article, a sub-microsecond compact
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-band relativistic Cherenkov oscillator (RCO) is studied. The device adopts a coaxial slow wave structure to reduce the radial size and a coaxial collector structure to improve the resonance characteristics of the slow wave structure to reduce the axial size. In particular, a coaxial outer corrugated slow wave structure is used instead of the coaxial double-corrugated slow wave structure to increase the power handling capacity (PHC) of the slow wave structure and reduce its surface electric field. Moreover, the collector structure has been improved to suppress the effects of plasma expansion. In the experiment, the device obtained a high-power microwave output with a microwave frequency of 1.496 GHz, a power of 2.0 GW, a pulsewidth of 317 ns (single pulse energy of 634 J), and a power conversion efficiency of 32%. The pulsewidth and the single pulse energy are the highest levels reported for the RCO.