High-power microwaves at 25 years: the current state of development

The field of high-power microwaves (HPM) has matured considerably in the 25 years since the initial development of relativistic backward wave oscillators (BWOs) by researchers from the Institute of Applied Physics and the Lebedev Institute in Russia and from Cornell University in the US. In this paper, we review some of the signs of the maturity of the field, including changes such as an observed narrowing in the number of source types under development, an increase in commercial suppliers, and a growing internationalization of the research field. In addition, within the context of historical developments in the field, we discuss the development of high peak power systems and the apparent abandonment of the pursuit of ever-higher power in favor of the development of gigawatt-level systems with manageable weight and volume, repetitive operation, and tunability.