Investigation of low voltage angular log-periodic folded groove waveguide slow wave structure for G-band TWT

A novel slow-wave structure (SWS) named angular log-periodic folded groove waveguide was proposed in this paper, which mainly used in traveling wave tube (TWT) for G-band. Due to the design idea owing the combination of folded groove waveguide and log-periodic form, this new SWS possess several advantages from them. Low operation voltage and weak dispersion of electromagnetic wave are merits of them. In addition, a modified equation to calculate the phase velocity in radial direction was proposed. In the end, one angular log-periodic folded groove waveguide was designed which owing 38.8W output power at 198GHz, the gain is 18.8dB when operation voltage is set to 8080V.