Three-Dimensional-Integrated Electron Optics System With Narrow Beam Separation for Terahertz Vacuum Devices

This article investigates a 3-D-integrated electron optics system (EOS) with narrow beam separation for fundamental-mode traveling-wave tube (TWT) in the
${W}$
-band. The integrated EOS is an innovative research direction that can integrate vacuum electronic devices (VEDs) on a large scale and increase their output power. Initially, an integrated electron gun with the three-layer nine-beam array is designed based on the grid loaded method, which is a universal method to obtain multibeam gun with narrow beam separation by 1-D (in the
${y}$
-direction) compression. The characteristic of an integrated electron gun is
$U_{a}$
= 22 kV and
${I} = 9\times0.15$
A. Subsequently, a novel scheme of a three-layer with a nine-beam array sharing a focusing structure is proposed to realize the stable transmission of nine-beam array, which can reduce the size of VEDs and enhance the power density. By continuously adjusting the relative positions of the integrated electron gun and the focusing structure along the
${z}$
-direction, a good matching state can be obtained with a high-beam transmission rate. The nine-beam array can transport 70 mm stably with a transmission rate of 98.6%. Finally, the whole system’s stability is verified, including variations of magnetic field, working voltage fluctuations, and assembly errors. The integrated EOS presents a novel approach for the large-scale integration of VEDs and can significantly improve the output power in the terahertz (THz) band.