Bragg resonator for selective feedback in overmoded oscillators

Summary form only given. Two Bragg resonators have been built for use in a 10-GHz CARM (cyclotron autoresonance maser)/gyro-TWT (traveling wave tube), one with sinusoidal corrugations and the other with rectangular corrugations. A Bragg reflection cavity is formed by separating two corrugated sections by a smooth section. The external quality factor for the cavity is given by Q_ext= kL/(1-R₁R₂), where R₁ and R₂ represent the reflection coefficients of the two corrugated sections, L is the length of the smooth section, and k=ω/c. The number of cavity modes within the reflector´s bandwidth is 2GL/π, where G is the coupling coefficient. The reflectivity of a single section and modes in the composite cavity for both the sinusoidal and rectangular corrugation reflectors were measured