Ka-band Dual-Anode Electron Gun, Beam focusing system and SWS for Space Applications

A electron gun of perveance $0.22 \mu$ p has been designed for Ka-band helix Traveling Wave Tube (TWT) which would ultimately have application in satellite communication system. Convergent electron gun with isolated beam forming electrode (BFE) & M-Type dispenser cathode with 3.1mm button diameter has been designed using codes EGUN. It consists of two isolated anodes namely control anode, ion barrier anode in addition to ground accelerating shaver anode to meet the requirement of long life & high reliability. Periodic Permanent (PPM) focusing structure has been designed using Sm
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high intensity magnet in order to reduce the size & weight of the overall TWT. Confined flow beam focusing has been adopted. A compact small size electron gun assembly has been designed using ceramic insulator & suitable support structure with due considerations for high voltage and thermal requirements. High voltage analysis has been carried out using code ESTAT and ANSYS for thermal analysis. Dual anode electron gun, focusing system and slow wave structure (SWS) has been experimentally validated by developing and testing Ka-band TWT prototypes having rated potentials. The design and experimental results are in close agreement.