Comparison Between Damping Coefficients of Measured Perforated Micromechanical Test Structures and Compact Models

TL;DR

This paper compares measured damping coefficients of perforated micromechanical structures with predictions from compact models, finding consistent underestimation and analyzing flow components to explain discrepancies.

Contribution

It provides an experimental validation of compact models for damping in perforated micromechanical structures and discusses reasons for underestimation.

Findings

Measured damping coefficients are about 20% higher than model predictions.

Perforation ratio varies from 24% to 59%.

Compressibility and inertia are negligible at tested frequencies.

Abstract

Measured damping coefficients of six different perforated micromechanical test structures are compared with damping coefficients given by published compact models. The motion of the perforated plates is almost translational, the surface shape is rectangular, and the perforation is uniform validating the assumptions made for compact models. In the structures, the perforation ratio varies from 24% - 59%. The study of the structure shows that the compressibility and inertia do not contribute to the damping at the frequencies used (130kHz - 220kHz). The damping coefficients given by all four compact models underestimate the measured damping coefficient by approximately 20%. The reasons for this underestimation are discussed by studying the various flow components in the models.