Abstract
Micro sonic sensors using piezoelectric diaphragm and cantilever have been developed in order to detect a weak specific sonic wave that is emitted from rotary machinery with anomalous behavior under a large background noise. A piezoelectric PbZr0.52Ti0.48O3 film was prepared on a micromachined SOI wafer by sol-gel method. The sonic wave response for the both diaphragm- and cantilever-sensors was investigated. The both sensors showed resonant peaks which are proportional to the reciprocal of the diaphragm-area and to the power of -2 of the cantilever-length in the frequency region over 5 kHz. The sensitivity and Q-value were estimated to be on the order of 10 mV/Pa and 100, respectively. It is also shown that a specific sonic wave can be detected by choosing several sensors with different diaphragm-area or cantilever-length.
