VHF free-free beam high-Q micromechanical resonators

Abstract

Free-free beam, flexural-mode, micromechanical resonators utilizing non-intrusive supports to achieve measured Q's as high as 8,400 at VHF frequencies from 30-90 MHz are demonstrated in a polysilicon surface micromachining technology. The subject microresonators feature torsional-mode support springs that effectively isolate the resonator beam from its anchors via quarter-wavelength impedance transformations, minimizing anchor dissipation and allowing these resonators to achieve high Q with high stiffness in the VHF frequency range.