“…Ultrasound (>20 kHz) is useful for a broad range of applications, from haptic devices to nondestructive testing, imaging, or wireless charging of medical implants. [ 25 , 26 , 27 , 28 , 29 , 30 , 31 ] In particular, emerging applications operating with ultrasound can benefit from the integration of efficient energy harvesting systems with the LAM. Examples include directional speakers, [ 32 , 33 ] Internet of Things devices or sensors [ 34 ] in dashboards of cars, and haptic devices, [ 35 ] which have become pervasive with virtual reality and augmented reality applications.…”