Conductor-centered arbitrarily-shaped helical-groove slow-wave structure for TWTs

Summary form only given, as follows. Helical-Groove waveguide(HGW) traveling wave tube (TWT) is one of the potential alternative candidates for high power millimeter wave sources. In this paper, we present the analysis of the novel helical-groove waveguides, the conductor-centered arbitrarily-shaped helical-groove structures, for a possible employment in a wide band TWTs in slow-wave regime. By making use of field theory and admittance, the dispersion relation, interaction impedance are derived. Numerical analysis has performed with HGW-2[3] code to investigate the physical parameters including the groove shape, the radius of the center rod on the wave properties of the electromagnetic (EM) wave propagating through the conductor-centered arbitrarily-shaped helical-groove structure. As it shown from the dispersion characteristics, the profile of the groove takes large influence on high cut-off frequency, passband and wave velocities. This analysis also shows the interaction impedance and small signal gain of TWT with the variation of the physical parameters, indicating the bandwidth of HGW-TWT can be increased largely by choosing a conductor-centered arbitrarily-shaped helical-groove structure with a triangle profile of the groove.