BANDWIDTH AND SENSITIVITY ENHANCEMENT OF PIEZOELECTRIC MEMS ACOUSTIC EMISSION SENSOR USING MULTI-CANTILEVERS

The bandwidth and sensitivity of piezoelectric MEMS acoustic emission (AE) sensors are enhanced using multi-cantilevers that are electrically connected in series. Compared with a single-cantilever sensor, the bandwidth and sensitivity are increased 5.3- and 2-fold, respectively, by using an array of 210 cantilevers. By optimizing the silicon-layer thickness, the sensitivity of the single-cantilever sensor can be improved 6-fold. As a result, even a smaller array of 10 cantilevers with the optimized layer thicknesses exhibits 2-fold enhancement of bandwidth and 4-fold enhancement of sensitivity. The AE-wave detection capability is demonstrated by the standard pencil-lead break test.