Broadband performance of a patterned piezoelectric energy harvester integrated with a continuous elastoacoustic mirror

In this work we explore efficient transformation of broadband wave energy into low-power electricity using patterned polymer piezoelectrics integrated with an Elliptical Acoustic Mirror (EAM) configuration. The mirror under consideration features a semi-elliptical continuous mirror with a rectangular arrangement of harvesting material overlapping the geometrical focus of the mirror. Spatial and temporal transformation of the wave propagation field into the frequency-wavenumber domain is performed in order to identify the wavenumber content inside the mirror region. A frequency-domain Root-Mean-Square (RMS) evaluation is then applied in order to guarantee broadband harvesting characteristics to the resulting Distributed Harvester (DH). Computational modeling and experimental testing are employed to quantify performance enhancement of the presented approach in the 20-120 kHz range, where broadband focusing characteristics of the continuous EAM are confirmed experimentally. Additionally the patterned configuration with proper wiring results in substantial power enhancement over 20-60 kHz, i.e. the neighborhood of the center frequency used in its Fourier transform-based design.