Design Study of a Sub-THz Traveling Wave Tube With a Converging Sheet Electron Beam

The results of simulation study aimed at development of a sub-THz traveling-wave tube (TWT) with a converged sheet electron beam are presented. The dual grating staggered slow-wave structure with a 100-um-height beam tunnel is designed and its cold electromagnetic parameters are calculated. The results of 3D PIC-simulation of the gain and output power in small-signal and large-signal operating regimes are presented. We compare the characteristics of the TWT driven with the converging sheet beam produced by an electron gun with shielded cathode and with a rectilinear beam produced by a gun immersed in the uniform magnetic field.