Terahertz backward wave radiation from the interaction of high-order mode and double sheet electron beams

Abstract

Terahertz (THz) radiation obtained from the interaction between multiple sheet electron beams and a backward wave operating in the high-order mode (HOM) provides an effective method to extend the operating frequency and power capacity. Suppression of the low-order mode (LOM) competition is one of the most important issues in the HOM operation for a backward wave oscillator (BWO). To address this issue, two ridges were introduced in the double staggered grating waveguide slow wave structure (SWS). The dispersion and transmission simulations of this improved SWS showed that a good frequency selective property was achieved and the LOM competition was effectively suppressed. Particle-in-cell simulations predicted that the HOM BWO could produce a THz-wave with clear frequency spectrum and obtain >0.46 W output power in the range of 1.19–1.24 THz. The proposed HOM BWO is a promising compact and powerful THz radiation source.