Enhancing interaction efficiency in traveling-wave devices with multiple beamlets and beam-beam interference

We demonstrate that beam-beam interference can significantly enhance the efficiency of multi-beam traveling-wave devices. Our theoretical analysis explains that a positive coupling of the space-charge field enhances the beam-wave interaction, resulting in increased efficiency in multi-beam devices with beam-beam interference. We validate this mechanism by performing particle-in-cell simulations on 670 GHz grid-loaded rectangular waveguide backward-wave oscillators. Both the multi-beam and single-beam devices exhibit the same dispersion of operating modes and operate under identical conditions. The simulation results indicate that the efficiency of the multi-beam device is up to 1.58 times higher than that of the single-beam device. Additionally, simulations are performed on the same structure at 340 and 1030 GHz, demonstrating efficiency improvements that support the proposed mechanism. These findings present a novel approach for increasing the efficiency of traveling-wave devices.