Sound energy harvesting by leveraging a 3D-printed phononic crystal lens

We investigate the harvesting of sound waves by exploiting a 3D-printed gradient-index phononic crystal lens. The concept is demonstrated numerically and experimentally for focusing audio frequency range acoustic in air to enhance energy harvesting. A finite-element model developed design unit cell dispersion properties construct 3D lens wave field simulations. Numerical simulations are presented confirm incident plane study sensitivity refractive index profile direction propagation. theoretical predictions validated using scanning microphone setup under speaker excitation, very good agreement observed between experimental numerical fields. circular piezoelectric unimorph harvester placed at focal position lens, its performance characterized with resistor sweep absence presence resulting more than an order magnitude enhancement harvested power here substantially enhances intensity via focusing, yielding micro-Watt level output, which can find applications wireless sensors other low-power electronic components.