Photolithography-based realization of frequency steerable acoustic sensors on PVDF substrate

Design, fabrication and testing of a frequency-steerable acoustic transducer (FSAT) is presented in this paper. The proposed device concept allows directional guided wave sensing for structural health monitoring (SHM) applications. The direction of an incoming wave is univocally encoded in the spectrum of the output signal thanks to the spatial filtering effect produced by the peculiar shape of the FSAT. Accurate localization of acoustic events within a two-dimensional half-plane can thus be performed with very small hardware and software complexity by processing the time-trace recorded by a single device. Photolithography-based fabrication on a polyvinylidene fluoride (PVDF) substrate provides a flexible and lightweight transducer with a number of attractive features for integrated and wireless SHM.