High-efficient converters of circular waveguide higher mode to the mode of simplest structure

The techniques for gyrotron operation mode conversion into a Gaussian-like wave beam are considered. Experimental results are presented on excitation of the TE12.5 mode (84 GHz) of the circular waveguide, and also on measurement of the wave beam parameters at the converter output when operating with a small level of electromagnetic power. The conversion efficiency is measured to be 97.5%.