Miniature Orotrons Utilizing Carbon Nanotube Cathodes

Summary form only given. The goal of producing THz radiation from miniature electron beam devices has refocused interest in orotrons. Here we consider planar orotrons driven by electron beams produced by carbon nanotube cathodes. The efficiency of these devices improves with increasing current density. However, with increasing current density, self-fields become more important. Here, the theory of self-fields in a planar orotron is developed. We find that the parameters of the grating, which provides the slow wave fields that interact with the beam, also affect the self-fields, which give rise to the slow space charge wave. Thus, optimization of the grating parameters requires consideration of their impact on the dispersive properties off the slow space charge wave. Thus, the field emitter arrays meet both the geometric and current-density requirements predicted for the orotron. miniature electron beam devices