A Curve-Structured Flexible Pmut with Enhanced Acoustic Sensitivity

A flexible PMUT with novel curved structure was proposed to enhance acoustic performance. The transducer was first simulated through finite element analysis to investigate the impact of curvature radius on properties. With a simulation optimized curvature radius (1.4 mm), a sandwich layer of bottom Au film, P(VDF-TrFE) film, and top Au film was fabricated on PET substrate, then was structured to curve form via hot-processing, following that a laser-processed PI cavity was adhered to the backside of PET elastic layer. The obtained PMUT demonstrated about a two-fold increase in both transmitting and receiving sensitivities, compared to the flat counterpart. Based on the time-of-flight mechanism, the curved flexible PMUTs were further introduced and successfully measured the variation of sugar content in liquid.