Evaluating the Influence of PMUT Mechanical Support Properties on Power Conversion Efficiency in Ultrasonically Powered Implants
Alessandro Stuart Savoia (University of Roma Tre)
Domenico Giustiniano (STMicroelectronics)
Carlo Prelini (STMicroelectronics)
M. Saccher (TU Delft - Electronic Components, Technology and Materials)
A. Rashidi (TU Delft - Bio-Electronics)
Alberto Leotti (STMicroelectronics)
Vasiliki Giagka (TU Delft - Bio-Electronics, Fraunhofer Institute for Reliability and Microintegration IZM)
Marco Ferrera (STMicroelectronics)
More Info
expand_more
Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.
Abstract
Micromachined Ultrasonic Transducers (MUTs) are being explored as power converters in wirelessly powered biomedical implants. This paper investigates the role of mechanical support properties in piezoelectric MUTs (PMUTs) on their power conversion efficiency. For this purpose, a finite element model (FEM) of a PMUT array was developed and integrated with an equivalent circuit model (ECM). The study considered different mechanical support scenarios, from rigidly clamped to completely free. These were numerically analyzed and validated by impedance measurements and acoustic power transfer experiments on PMUT prototypes. The results show that reducing the mass of the mechanical support increases the Q factor, leading to a significant improvement in power conversion efficiency, with an efficiency increase factor of 5.6x from the clamped to the free case. This approach can potentially enhance overall power conversion efficiency, reduce the need for matching networks, and enable miniaturization in ultrasonically powered implants.