Powerful Oversized Surface-wave Oscillators with 2D-periodical Slow-wave Structures of Cylindrical Geometry Operating in W and G Bands

Projects of spatially-extended short-wavelengths Cherenkov Surface-Wave Oscillators (SWO) of cylindrical geometry are being developed at the IAP RAS based on the high-current accelerator "Sinus-6" forming a large-size tubular electron beam of 0.5MeV/5kA/25ns. At the current stage, SWO were implemented in the W-band (operating frequency is about 73GHz) and G-band (frequency ~ 150GHz) with an oversize parameter (diameter), amounting to 10 and 20 wavelengths, respectively. The key component of these generators is a doubly-periodical slow-wave structure, which implements a two-dimensional distributed feedback mechanism and provides selective excitation of the operating mode in conditions of such extremely high oversize. As a result of the experiments, stable narrow-band generation was achieved at design parameters with a record output power level of 120–150MW in the W-band and up to 50MW in the G-band. In accordance with the simulations, the obtained oscillation regimes were characterized by an azimuthally-symmetric structure of the output radiation.