Electromagnetic Field Shaping for Efficiency Enhancement in Terahertz Folded-Waveguide Traveling-Wave Tube Slow-Wave Circuit Design

In this paper, there is much interest in using vacuum electronics in the terahertz regime because of their superior power and efficiency capabilities compared to solid state power amplifiers (SSPA's) at high frequencies. However power and efficiency levels with conventional vacuum electronics devices are still quite low in the terahertz regime because of the small size of the circuits and high attenuation. In this presentation, we will show computational results from our investigation of using holey metamaterials, corrugations, and frequency selective surfaces for electromagnetic field shaping to increase the efficiency and power in terahertz folded- waveguide travelling-wave tube slow-wave circuits.