A 0.34-THz High-Power, Slow-Wave Structure: Designing and Microfabricating an H-Plane Ridge-Loaded Folded Waveguide

High-power microvacuum electronic devices are one of the key technologies for the study of terahertz radiation sources. The traveling-wave tube (TWT) based on the folded waveguide slow-wave structure is the most promising terahertz device. This article designs the structural parameters of an H-plane ridge-loaded folded waveguide to improve the maximum output power of TWTs in the atmospheric window at 0.34 THz. The results predicted by a theoretical model and by electromagnetic (EM) simulation indicate the interaction impedance of the slow-wave structure is significantly increased. The simulation results show that the design is capable of raising the maximum output power to more than 50 W at 0.34 THz, with sheet electron beam parameters of 16.8 kV and 50 mA. The power gain, the 3-dB bandwidth, and the electronic efficiency of the folded waveguide can reach 30.5 dB, 10 GHz, and 6%, respectively. Finally, the designed slow-wave structure is microfabricated using multistep UV-LIGA technology.