Relativistic Cherenkov Microwave Oscillator Without a Guiding Magnetic Field for the Electron-Beam Energy of 0.5 MeV

The feasibility of a relativistic Cherenkov microwave oscillator with no magnetic field for an electron-beam energy of ~0.5 MeV is studied. The oscillator geometry, with an efficiency of electron-beam power conversion to microwave radiation of ~20%, is simulated. The estimated radiation power is 400 MW. In the experiment, stable oscillation with ~6% efficiency is realized, taking into account the total current of a planar diode producing the electron beam. The microwave peak power for the operating TM
₀₁
wave was 140 ± 30 MW at 3.82 GHz.