Design and Fabrication of a Narrow-Bandwidth Micromechanical Ring Filter using a Novel Process in UVLIGA Technology

This paper presents a novel low-cost fabrication process for micromechanical filter in uv-liga technology. the micromechanical filter consists of the two identical bulk-mode ring resonators, mechanically coupled by a flexural-mode beam. the design procedure is performed by a mechanical lumped element model and ansys software. the low-cost fabrication process with only three uv-lithography steps is used to achieve a high aspect ratio of 20 with 3 ìm gap spacing. the fabricated filter is characterized using a fully differential drive and sense interface circuit. the experimental results demonstrates micromechanical filter with a center frequency of 10.31 mhz and percent bandwidth less than 0.3% using a dc-bias voltage of 60 v. the detailed fabrication process can be applied as an appropriate alternative to x-ray liga and silicon-based micromechanical filters.