Design of a Highly Efficient Metamaterial-Assisted Electron-Beam Structure for x-band Backward Wave Oscillator Applications

In this article, a beam-wave interaction simulation of metamaterial (MTM)-assisted electron-beam structure is presented. The electron-beam structure is formed by an array of
${x}$
-band complementary electric split ring resonators (CeSRRs) inserted into a circular waveguide. CST Particle Studio is used for the beam present simulation of the MTM-assisted electron-beam structure. With typically selected beam voltage of 190 kV, beam current of 11 A, and focusing magnetic field of 0.39 T, the particle-in-cell (PIC) simulation predicts an average RF output power of ~0.96 MW with a conversion efficiency of ~46%. The proposed MTM-assisted electron-beam structure, with its high-efficiency capability, can have the potential applications in possible microwave oscillators, i.e., backward wave oscillators (BWOs).