A Wideband 220-GHz Traveling Wave Tube Based on Slotted Piecewise Sine Waveguide

A slotted piecewise sine waveguide (SPWSWG) is suggested as the slow wave structure (SWS) to develop the terahertz traveling wave tube (TWT). This letter is the first to report the SPWSWG SWS with the advantages of flat dispersion and large coupling impedance from our calculation. Based on this novel SWS, a wideband 220-GHz TWT has been designed, fabricated and tested. The cold test results show that the reflection parameters at the input and output port of the TWT are less than −15.2 dB in the frequency range of 209–235 GHz. Moreover, the hot test results demonstrate that the maximum saturated output power reaches 28.6 W at 215 GHz and the 3-dB bandwidth exceeds 15.5 GHz, which are basically consistent with the simulation results.