Oversized Ka-band surface-wave oscillator based on 2D periodical corrugated structure

Ka-band surface wave oscillator of a cylindrical geometry driven by tubular electron beam 300 keV / 100 A / 3 μs has been realized. Narrow-band regime of oscillations in strongly oversized system (perimeter-to-wavelength ratio is about 16) was achieved using periodical structure with two-dimensional corrugation. Output power of 1.5-2 MW level was obtained. High stability of the oscillation frequency with respect to variation of the electron beam parameters was demonstrated. In accordance with the results of simulations, frequency stabilization is caused by the presence of transverse (azimuthal) energy fluxes provided by 2D corrugated structure. The project of a Ka-band sub-gigawatt surface wave oscillator based on “SINUS-6” accelerator (500-700 keV / 4 kA / 20 ns) is developed.