Relativistic microwave oscillators with high power flux in a free space and interaction zoneM.I. Yalandin, M.S. Pedos, V.V. Rostov, I.V. Romanchenko, S.N. Rukin, K.A. Sharypov, S.A. Shunailov and M.R. UlmaskulovEPJ Web Conf., 149 (2017) 01014DOI: https://doi.org/10.1051/epjconf/201714901014