Development of electron-optical system with three elliptic electron beams for a THz-band vacuum-tube device

The results of design, simulation, and experimental testing of an electron-optical system with three elliptic electron beams are presented. Total beam current is 93 mA. The beams are focused by a PPM system with 0.55 T magnitude of the magnetic field. Beam transmission in a rectangular tunnel at over 25 mm distance is demonstrated. The developed electron optical system is assumed to be used in sub-THz-band vacuum-tube devices such as O-type traveling-wave tube or backward-wave oscillator. Electromagnetic parameters of a double-grating staggered slow-wave structure are calculated.