A profiled stepped reflector for mode selection in power microwave generators of ultrashort pulses

elective reflection of a spatially-developed mode of a cylindrical waveguide is investigated as applied to a radiation output and a feedback circuit closing in power microwave generators of ultrashort pulses. The profile and the ratio of the parameters of the stepped reflector has been found providing the maximum suppression of the spurious modes at the given loss level of the working mode within the wide frequency band. It is shown the frequency bandwidth of the reflector of the axial-symmetric mode $E_{02}$ reaches 10% over the level 0.9 relative to the maximal value of the reflected power.