The analytical design of a folded waveguide slow-wave structure for THz TWT

A simple method based on the physics characteristics to get the main parameters of folded waveguide traveling wave tube (TWT) circuit is present. Providing the operating frequency and beam voltage, we can obtain the initial structure parameters of the folded waveguide slow-wave structure. An 220GHz folded waveguide slow-wave structure is designed to verify this method. The cold characteristics including dispersion relation and interaction impedance are analyzed. The large signal performance of folded waveguide circuit is predicted by PIC code.