High-selectivity resonator for powerful microwave sources

A simple and effective method for providing of single-mode operation regime of relativistic microwave generators with oversized electrodynamic system is suggested. Required solitary structure of microwave field is achieved by additional channels of selective feedback. Such method is realized in resonant traveling wave tube (TWT) in which a stable operation with output radiation in the form of Gaussian wave beam is obtained with combination of Bragg type reflectors with different azimuth symmetry of their wall corrugation.