High-Q Cylindrical Alumina Resonator Based on Bragg Confined Mode of Azimuthal Mode Number Greater Than Zero

The author´s report on the observation of a new type of Bragg confined mode in a dielectric loaded cavity. The structure is built from a hollow single layer dielectric cylinder loaded in a silver plated copper cavity. A resonance was observed at 13.4 GHz with an unloaded Q-factor of order 2 x10⁵ , which is more than a factor of 6 above the dielectric loss limit. Previously such modes have only been realized from pure Transverse Electric modes with no azimuthal variations and only the E component. From simulations using a rigorous numeric technique it is shown that the mode has non-zero azimuthal variations and with dominant E_r and E electric field components and H_z magnetic field component.