In this paper we introduce the concept of thespherical Bragg reflector (SBR) resonator. The resonatoris made from multiple layers of spherical dielectric, loadedwithin a spherical cavity. The resonator is designed to concentratethe energy within the central region of the resonatorand away from the cavity walls to minimize conductorlosses. A set of simultaneous equations is derived,which allows the accurate calculation of the dimensions ofthe layers as well as the frequency. The solution is confirmedusing finite-element analysis. A Teflon-free space resonatorwas constructed to prove the concept. The Teflon SBR wasdesigned at 13.86 GHz and exhibited a Q-factor of 22,000,which agreed well with the design values. This representsa factor of 3.5 enhancement over a resonator limited bythe loss-tangent of Teflon. Similarly, SBR resonators constructedwith low-loss materials could achieve Q-factors ofthe order of 300,000.
|Journal||IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control|
|Publication status||Published - 2004|