A 220 GHz Traveling-Wave Tube Based on a Modified Staggered Double Corrugated Waveguide

Staggered double-grating slow-wave structures (SDG-SWSs), which are easy to fabricate and have broadband characteristics, play a core role in research on high-power terahertz (THz) traveling-wave tubes (TWTs). However, their relatively low interaction impedance restricts further improvements in the output power of SDG-TWTs. A modified staggered double corrugated waveguide (MSDCW) SWS that evolved from a staggered double corrugated waveguide (SDCW) SWS is proposed in this study for the first time. The MSDCW-SWS has both the advantages of a wide bandwidth and a high interaction impedance. The width of the beam tunnel also has little effect on the lower cutoff frequency. High-frequency calculations reveal that the passband of the MSDCW-SWS is 10 GHz wider than that of the SDG-SWS, and the interaction impedance is about 1.34 ohm higher than that of the SDG-SWS and 1.07 ohm higher than that of the SDCW-SWS at 220 GHz when the dispersion is the same. The results of the interaction simulation show that the MSDCW-TWT has a maximum gain of ~22.11 dB with a maximum output power of ~117 W and a maximum electron efficiency of ~2.64% at 220 GHz with an electron beam of 24.6 kV and 180 mA. The MSDCW should therefore be considered as a promising SWS for high-power and wideband THz traveling-wave amplification.