Development of Electron-Optic System with Compression of Multiple Elliptic Electron Beam

Multiple-sheet-beam traveling-wave tubes (TWTs) for high-power, wideband operation at sub-THz and THz frequencies have attracted a strong interest. Using electron-optic systems (EOSs) with compression allows reduce of the cathode loading and enables operation in a continuous-wave (CW) mode. However, it is difficult to develop an EOS with high compression of a multiple sheet electron beam. In this article, we present the results of development of EOS producing a triple elliptic-shaped electron beam. Two designs with the compression rate of 6.4 and 16, respectively, are presented. The electron guns consisting of an impregnated thermionic cathode, a shadow grid, a planar control grid, and an anode with the beam tunnel are designed and fabricated.