| 摘要 |
<p>A flexural-mode, micromechanical resonator utilizing a non-intrusive support structure to achieve measured Q's as high as 8,400 at VHF frequencies from 30-90 MHz is manufactured using polysilicon surface micromachining technology. Also, a method for extending the operating frequency of the resonator as well as other types of micromechanical resonators is disclosed. One embodiment of the method is called a differential-signaling technique. The other embodiment of the method is called a dimple-down technique. The support structure includes one or more torsional-mode support springs (16) in the form of beams that effectively isolate a resonator beam from its anchors (18) via quarter-wavelength impedance transformations, minimizing anchor dissipation and allowing the resonator to achieve high Q with high stiffness in the VHF frequency range. The resonator also includes one or more spacers (26) in the form of dimples formed on the flexural resonator beam (12) or the substrate. In operation, the dimples (26) determine a capacitive-transducer gap of the resonator. When a large DC-bias voltage is applied between a drive electrode (20) and the resonator beam (12), the dimples (26) provide a predetermined minimum distance between the flexural resonator beam (12) and the drive electrode (20).</p> |
