Design of a W-Band Sheet Beam Extended Interaction Klystron Working at $2\pi\text{-Mode}$

A W-band sheet beam extended interaction klystron (SBEIK) with three five-gap cavities is designed and optimized in this paper. The cold-test simulation results shows that the stable
$\mathbf{TM}_{\mathbf{11}}-\mathbf{2}\boldsymbol{\pi}$
operating mode is achieved at 93. 8GHz. The particle-in-cell (PIC) simulation results shows that the continuous wave output power of the EIK is 496.3W and an electronic efficiency is 3.19%, driven by a 14.1kV,1.2A sheet beam in a 0.5T magnetic field respectively.