Flexible, Compact Acoustic Transducer Arrays

The main limitations in the use of conventional sensor arrays for acoustic reconnaissance are its required size and its rigid structure. In order to overcome these limitations without compromising the array sensitivity, it is of crucial importance to develop new concepts and techniques allowing sound concentration in small areas, directivity values beyond the conventional limits related to the total array size, and a flexible configuration. The broad class of acoustic metamaterials (MMs) appears to be the perfect candidate to solve these problems. In this proposal, we pursue two approaches to obtain flexible, compact acoustic sensor arrays: 1) improve current transducers with the introduction of MM elements and 2) design innovative classes of acoustic MM sensor arrays with increased angular sensitivity. We investigate the possibility to realize ultrasensitive arrays of transducers by broadband funneling of acoustic waves using broadband MMs for nonresonant matching of acoustic waves and acoustic zero-density MM channels for funneling and large phase control. We also study MM ultracompact transducers with superdirective properties, bio-inspired nonlinear acoustic transducers and acoustic superresolving transducer arrays.