© E.E. Lysenko, O.F. Pishko, V.G Chumak, and S.A. Churilova

Considered in the paper are prospects for practical implementation of sub-millimeter band, CW clinotrons with output power levels above 100 mW. Prototype devices are discussed, featuring waveguide-based and distributed quasioptical energy extract at 300 to 400 GHz. A specific clinotron design is described, implementing the distributed quasioptical principle of energy extract. Start-up and steady-state operation regimes have been analyzed, which allowed revealing behavior features characteristic of the said frequency range (300 to 400 GHz), hence enabling optimization of the slow-wave structure geometry and that of the interaction space. Results of the experiments aimed at investigating details of electron-wave interaction in the devices under development are discussed, and comparison is done with similar studies in the shorter wavelength part of the millimeter range. Recommendations are suggested concerning fine adjustment of the device in a magnetic field. A technique is described for optimizing output parameters of the clinotron with a distributed quasioptical energy extract. Frequency characteristics and output parameters of the clinotrons are presented. As has been found, employment of the distributed quasioptical energy extract may increase the power output to the level of 700 mW.