Modeling and Measurement of an Ultrasound Power Delivery System for Charging Implantable Devices Using an AlN-Based...

Area of Science:

• Biomedical Engineering
• Materials Science
• Acoustics

Background:

• Wireless power transfer is crucial for implantable medical devices.
• Ultrasound offers a promising non-ionizing method for intra-body power transmission.
• Existing methods face challenges in efficiency and biocompatibility.

Purpose of the Study:

• To model and experimentally validate an intra-body ultrasound power delivery (UPD) system.
• To characterize the performance of piezoelectric transducers for wireless power transfer within biological tissues.
• To assess the feasibility of using biocompatible materials for implantable power systems.

Main Methods:

• Developed a system using Langevin and AlN-based micro-machined ultrasonic transducers.
• Utilized polydimethylsiloxane and stainless steel to simulate human tissue and implant casing.
• Conducted experimental measurements of transducer impedance, phase, velocity, displacement, acoustic pressure, voltage, and power output.
• Validated experimental results with a 1D lumped parameter transmission line model.

Main Results:

• Characterized transducer behavior including impedance, phase, velocity, displacement, and acoustic pressure fields.
• Achieved a power density of 21.6 µW cm^-2 at a 35 V root mean square input voltage.
• Experimental results closely matched simulation data from the 1D transmission line model.

Conclusions:

• The proposed ultrasound power delivery system is a valid design for charging implantable devices.
• The use of non-toxic, biocompatible materials is suitable for intra-body power transfer components.
• This research supports the advancement of wireless power transfer technologies for medical implants.