Speaker
Description
Relativistic klystron amplifier is a promising device to lock and steer the phases of high power microwave radiations, by which coherent combining of multiple radiations can be achieved to enhance the total equivalent radiation power. We report the investigations on coherent combining of phase-steerable high power microwaves (HPMs) generated by X-band relativistic triaxial klystron amplifiers which function like seeded free-electron masers that yields coherent emissions by the mechanism of transition radiation. It was found that electronically agile manipulation of the HPM phase is achieved with a mean discrepancy of 4° at the gain level of 110 dB. The coherent combining efficiency has reached remarkably as high as 98.4%, leading to combined radiations with equivalent peak power of 4.3 GW in X-band and average pulse duration of 112 ns. Owing to high spatial and temporal coherences, the presented gigawatt-class HPMs with electronic agility in phase may be applied to many other fields, for example, to drive high-gradient accelerators or to build coherent high power radars even with phase coding, and this study may also excite new interest in more comprehensive research in phase-steerable masers and their applications.