Exploring a Three-Electron-Beam Frequency Multiplication Amplifier Based on Super-Radiant Smith-Purcell Radiation

In this manuscript, a super-radiant Smith-Purcell radiation (S-SPR) based triple-electron-beam frequency multiplication amplifier operating at
${W}$
-Band is proposed. The high-frequency structure of the proposed amplifier consists of a multigap extended interaction resonant cavity as the input cavity and a quasi-optical open resonant cavity with gratings as the output cavity. The high-frequency structure is designed to cooperate with three cylindrical electron beams (e-beams) for high beam current and easy focusing. The e-beams travel through the tunnels drilled in the gratings, leading to a high beam-wave interaction efficiency and radiation intensity. The particle-in-cell (PIC) simulation results show that the output power of the proposed device is between 115.52 and 364.5 W, with a gain of 37.62–42.61 dB, and an input power of 0.02 W. The effects of the beam number and position have also been investigated. By properly design of the electron-optical system (EOS), the e-beams are able to transmit 18 mm stably under the uniform magnetic focusing system, with the voltage and current of 14 000 V and
$3\times0.295$
A, respectively. The device proposed in this article is expected to be applied to high-power and compact terahertz radiation sources.