ThroughSupport-Coupled Micromechanical Filter Array

This paper presents a new concept for implementing high-order mechanically-coupled ultra-small bandwidth micro-mechanical filter arrays without using discrete coupling elements. Adjacent resonators are coupled by elastic deformation at the support, and filter bandwidth is defined by the spacing between resonating elements. We demonstrate a second-order through-support-coupled capacitively-transduced 1.72MHz 0.008%BW (Qfilter≈12000) bandpass flexural-mode beam filter array implemented on SOI. The coupling concept and experimental results were verified with finite element analysis using ANSYS. This integrated coupling technique does not introduce additional fabrication requirements for a discrete mechanical coupling element and therefore has strong potential for application to high-order higher frequency filter arrays. Resonator fine tuning is shown to be essential for obtaining ultra-small coupling-limited filter bandwidths. 1