The growing need for high performance but low power microelectromechanical system (MEMS) devices capable of operating at various frequency regimes, including high frequency (HF), very high frequency (VHF) and ultra-high frequency (UHF), fuels an increasing demand for resonators with simultaneous high quality factor (Q) and high electromechanical coupling, as gauged by the motional-to-static capacitive ratio (Cx/Co). Capacitive-gap transduced resonators have already posted some of the highest disk Cx/Co-Q products to date at HF and low-VHF. Attaining similar performance at the high-VHF and UHF ranges, however, if more difficult, as it requires electrode-to-resonator gaps considerably smaller than previously demonstrated.
This thesis explores a method that raises Cx/Co without excessive gap scaling by hollowing out a disk resonator structure, which reduces the dynamic mass and stiffness of the structure. Since Cx/Co goes as the reciprocal of mass and stiffness, a hollow disk can have considerably stronger electromechanical coupling than a solid one at the same frequency. This work introduces two types of hollow disks: asymmetric and symmetric.