Development of W-band sheet beam klystron with high transmission rate electron optics system

In this paper, the development of W-band sheet beam klystron has been introduced with high transmission rate beam and a 2-dimensional code SBK2D calculation. The ellipse cathode and electrode structure is used to form the sheet electron beam with the beam aspect ratio about 25:1. And the uniform magnetic system is used to transport the sheet electron beam with the drift tube length about 100mm. After the sheet beam tube is manufactured, the transmission rate and cross-section experiment are performed. With the beam voltage of 20-82 kV, and beam current of 0.5-4.2A, the transmission rate is more than 98%, and the beam cross-section is about 10×0.5mm². Then the sheet electron beam wave interaction process with 4 single-gap and 4 multi-gap cavities are calculated using the 2-dimensional code SBK2D based on the rod shape macro-particle model, the 55kW high frequency output with the efficiency of 20% and gain of 40 dB are observed at the frequency of 94.5 GHz.