Electron-optical System for a Q-band Helix Traveling-wave Tube

In this paper, an electron-optical system for a Q-band traveling-wave tube (TWT) is proposed to meet the demand of future wireless communications. Based on the electron beam parameters required for the Q-band TWT, a dual-anode electron gun and periodic permanent magnet (PPM) focusing configuration are designed. The CST simulation results show that the beam voltage, current and waist radius of the pencil electron beam are 8.7 kV, 70 mA, and 0.135 mm, respectively. The electron beam can transport through the helix slow-wave structure with a length of more than 100 mm and the static beam transmission can reach over 99.8% in CST simulation.