Design Approaches and Electromechanical Modeling of Conformable Piezoelectric-Based Ultrasound Systems

Abstract

Painless, needleless delivery of drugs through the skin can be realized through aphenomenon called sonophoresis by applying an ultrasound field to the biological tissue. Development of wearable embodiments of such systems demands comprehensive characterization of both the physical mechanism of sonophoresisas well as wearability parameters. Here, we present a framework for analyzing disk-type piezoelectric transducers in a polymeric substrate to create acoustic cavitation in a fluid coupling medium for sonophoresis applications. The device design and operating parameters such as the working frequency, applied voltage range, acoustic pressure distribution, and transducer spacing were determine dusing a finite element methods (FEM),and verified with experimental measurements. The influence of the surrounding water and tank reflections on the acoustic pressure field, and the interaction between the elements in the array structure were also studied.Finally, the impact of skin and the substrate geometry on the acoustic pressure fields was characterized to simulate the invivo use-case of the system. These analytical models can be used to guide critical parameters for device design such as the separation distance of the piezoelectric transducer from the skin boundary. We envision that this tool boxwill support rapid design iteration for realization of wearable ultrasound systems.