Initial Engineering Design for the Implementation of a “smart Tube” Frequency- Agile, High Power Bwo

Recent work at the University of New Mexico (UNM) by Morelan~ et al. (1) has demonstrated how 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. This enhanced band~vidtll is obtained through the axial displacement of the slow wave structure with respect to the cutoff neck “inlet” to the electrodynamics system. This paper describes the initial engineering design for accomplishing this displacement automatically to facilitate the incorporation of a robust controller, as proposed by Abdallah, et a/. (2). The purpose of this controller is to demonstrate a “smart tube” where a variety of objectives, such as i) maximizing the frequency bandwidth for a given constant power output, ii) maximizing the radiated peak prover at a given frequency, or iii) maximizing the beam-to-microwave power conversion efllciency, can be achieved automatically.