Progress on implementation of a frequency agile, high power backward-wave oscillator

Summary form only given, as follows. Recent work at the University of New Mexico has demonstrated that finite length effects in a high power vacuum backward wave oscillator (BWO) can be exploited to achieve frequency agility for constant beam and magnetic field parameters. Specifically, the axial displacement of the slow wave structure with respect to the cutoff neck "inlet" to the electrodynamic system results in a periodic variation of both radiated power and frequency. In this presentation we discuss progress in automating this axial "shifting" on a shot-to-shot basis using compact precision motors. This capability will then facilitate the use of a robust controller to achieve various control objectives. In particular, the preliminary design of a controller to i) maximize the frequency bandwidth for a given constant power output, ii) maximize the power radiated at a given frequency in the bandwidth, and iii) maximize the beam-to-peak microwave power conversion efficiency will be presented.