High Q Bragg resonators are studied for application to millimeter wave CARM oscillators driven by electron beams with power greater than 100 MW. ‘Whispering-gallery’ modes are shown to have the highest Q. The two effects that cause reflections, impedance mismatch owing to variations in the wall radius and currents driven in the walls of the reflector sections, are shown to compete, paving the way for anomalously lowQ s for some of the other modes. The effect of wall resistance on the operation of the cavity is studied; as the frequency of the radiation is increased to near 250 GHz, wall heating severelylimits the average power rating of whispering-gallery devices.
ASJC Scopus subject areas
- Electrical and Electronic Engineering