High confined Bragg modes for very low phase noise oscillator and narrow band filtering applications

This paper describes the use of a new resonator using a hybrid Bragg mode (HBM) with azimuthal variations greater than zero. Usually Bragg modes require a pure transverse electric mode with no azimuthal variations and only electric field component, E₀. The mode is both Bragg-like, (E_r is tangential to all dielectric boundaries) and also whispering gallery-like, (possesses azimuthal variations). This new dielectric resonator has superior performance with respect to typical dielectric resonators at room temperature. A resonance was observed at 13.4 GHz with an unloaded Q-factor of order 2times10⁵ in an alumina structure, which is more than a factor of six above the dielectric loss limit.