Study of a 0.3-THz Extended Interaction Oscillator Based on the Pseudospark-Sourced Sheet Electron Beam

Our previous experimental study of a 0.2-THz extended interaction oscillator (EIO) driven by the pseudospark-sourced (PS) sheet electron beam has revealed one key issue: the discrepancy between the simulated and measured output power was dramatically large. Around this issue, the design and analysis of an improved 0.3-THz EIO are presented in this article. To make the prediction closer to the actual situation, a few factors, including the plasma effect, the ohmic loss caused by the surface roughness, the effective beam current, and the energy spread, are analyzed and considered in the simulations. The plasma is equivalent to a dielectric. To verify the design, the interaction circuit of the 0.3-THz EIO was microfabricated. Its RF performance was measured by using a vector network analyzer, which was in good agreement with the simulation prediction, and its surface roughness was measured by using an optical 3-D surface profiler. Beam-wave interaction simulations having considered the ohmic loss, energy spread, and plasma effect predicted that the upgraded EIO still could produce an output power of 16.3 W at 295.3 GHz.