RESUMO
Generally, it is difficult for the common backward wave oscillator (BWO) to produce powerful THz radiation when the operating frequency increases to a high level such as over 1 THz due to the very small structural dimensions. The concept of generating powerful THz radiation from the interaction between high-order mode THz wave and multiple sheet electron beams is a promising solution to address the issue. For the high-order mode operation, a novel orthogonal grating waveguide is proposed, which is relatively ease of fabrication compared with the overmoded structure based on the double staggered grating waveguide. A high-order mode BWO based on the orthogonal grating waveguide and multiple sheet electron beams is studied by simulations. Particle-in-cell simulations show that the BWO can provide over 1.08 W power in the frequency range of 1.18-1.30 THz. Such a methodology opens up a new way to extend the BWO's operating frequency to a higher level and provides a potential solution for developing compact powerful THz radiation sources with wide tunable bandwidth.
