IC-compatible microelectromechanical intermediate frequency filters using integrated resonators with Q's in the thousands to achieve filter Q's in the hundreds have been demonstrated using a polysilicon surface micromachining technology. These filters are composed of two clamped-clamped beam micromechanical resonators coupled by a soft flexural-mode mechanical spring. The center frequency of a given filter is determined by the resonance frequency of the constituent resonators, while the bandwidth is determined by the coupling spring dimensions and its location between the resonators. Quarter-wavelength coupling is required on this microscale to alleviate mass loading effects caused by similar resonator and coupler dimensions. Despite constraints arising from quarter-wavelength design, a range of percent bandwidths is still attainable by taking advantage of low-velocity spring attachment locations. A complete design procedure is presented in which electromechanical analogies are used to model the mechanical device via equivalent electrical circuits. Filter center frequencies around 8 MHz with Q's from 40 to 450 (i.e., percent bandwidths from 0.23 to 2.5%), associated insertion losses less than 2 dB, and spurious-free dynamic ranges around 78 dB are demonstrated using low-velocity designs with input and output termination resistances of the order of 12 k/spl Omega/.
展开▼
机译：已经使用多晶硅表面微加工技术证明了与IC兼容的微机电中频滤波器，该滤波器使用具有数千个Q的集成谐振器来实现数百个Q的滤波器。这些滤波器由两个通过软弯曲模式机械弹簧耦合的夹钳式梁微机械谐振器组成。给定滤波器的中心频率由组成谐振器的谐振频率确定，而带宽由耦合弹簧尺寸及其在谐振器之间的位置确定。在此微米级上需要四分之一波长耦合，以减轻由相似的谐振器和耦合器尺寸引起的质量负载效应。尽管四分之一波长设计带来了一些限制，但通过利用低速弹簧附件位置，仍然可以获得一定范围的带宽百分比。提出了一个完整的设计过程，其中使用机电类比通过等效电路对机械设备进行建模。使用带有输入的低速设计展示了滤波器中心频率在8 MHz附近，Q为40到450（即，带宽百分比从0.23到2.5％），相关的插入损耗小于2 dB，无杂散动态范围大约为78 dB。输出端接电阻约为12 k / spl Omega /。
展开▼
