Terahertz Band Traveling-Wave Tube Based on Folded-Waveguide Slow-Wave Structure With Multiple Sheet Beams

A novel multiple sheet beams (MSBs) slow-wave structure (SWS), the horizontal multiple sheet beams folded-waveguide SWS (HMSB-FW SWS), was proposed for terahertz (THz) traveling-wave tubes (TWTs). This design aims to enhance the output power and meet the increasing demand for high-frequency and high-power THz radiation sources used in various applications. By utilizing MSB, the HMSB-FW SWS aims to improve the interaction between the electron beam and the electromagnetic wave. Compared with a vertical multiple sheet beams FW-SWS (VMSB-FW SWS), the HMSB-FW SWS offers a higher interaction impedance, leading to enhanced output power and gain. Simulation results indicate that the proposed HMSB-FW TWT exhibits significant improvements by over two times compared with the VMSB-FW TWT in amplification performance. Based on simulation results, with a magnetic field of 0.6 T and driven by an input signal at a frequency of 230 GHz, a saturated power of 100 W was obtained with a gain of 23 dB, an electron efficiency of 10%, and a 3-dB bandwidth of 20 GHz. Due to the limited fabrication accuracy at THz band, the FW-SWS requires specific tolerance and manufacturing compatibility. A study on zero-drive oscillations was performed to assess the stability of the proposed MSB-FW TWT.