Advantages of doublet modes for high-power millimeter-wave generation

The application in vacuum electron oscillators of degenerated modes, which are split due to absence of the exact symmetry of oscillatory circuits, is considered. General peculiarities of the interaction of electron flows with such modes are described. The spatial-harmonic magnetron oscillator is used as a practical example of the study. It is shown that the usage of doublet modes weaken size restrictions on the oscillator cavity design, can provide higher values of the device efficiency, as in spatial-harmonic maimeter-wave magnetrons, or a wide range of frequency tuning, like in the case of clinotrons.