Power Enhancement of Subterahertz Extended Interaction Oscillator Based on Overmoded Multigap Circuit and Linearly Distributed Two Electron Beams

In this article, a scheme with a designed overmoded multigap circuit based on the TM₁₃ mode and linearly distributed two electron beams is proposed for power enhancement of sub-THz extended interaction oscillators (EIOs). The analysis of the electromagnetic characteristics shows that the designed circuit can reproduce the resonant frequency, field distribution, and ohmic loss of the conventional multigap circuit with a single beam. When considering the same beam power injected into the designed and conventional circuit, the analysis of the beam loading shows the same effect on the circuit oscillation through the comparison in the electron conductance between two circuits. To examine the performance of the designed circuit, the EIOs are designed with two circuits at 0.22 THz. The analysis of the coupling coefficients between two circuits, combined with pic simulations, shows that the designed circuit produces the efficient interaction with two beams and, most importantly, two beam–wave interaction units can promote and achieve each other. The EIO with the designed circuit can deliver kW-level power at 0.22 THz. Accordingly, the proposed scheme has shown great potential in enhancing the power of sub-THz EIOs.