Ultrasound Wave Patterning for Spatiotemporal Control of Acoustic Power Transfer: Pathways from Transmission to Reception

Abstract

Ultrasound power transfer (UPT) is a promising technology that enables devices to receive energy wirelessly using high-frequency sound waves. This approach is especially important for medical tools, environmental sensors, and everyday electronics, offering a cleaner, more efficient alternative to traditional power sources. While UPT systems have come a long way, there are still major challenges in understanding and improving how acoustic waves behave as they move through different materials. This dissertation introduces new ways to model and test ultrasound power transfer, helping to boost both output power and efficiency. One focus is on a phenomenon called mode coupling, where different vibration modes interact and exchange energy. By predicting and managing this effect, the system's performance can be significantly improved. The work also presents a smart electrode design technique that allows UPT systems to operate effectively across multiple frequencies—an important step for real-world versatility. Another key part of this research is the use of acoustic holography, which shapes acoustic waves with great precision using 3D-printed lenses. These lenses can create complex acoustic patterns but have traditionally lacked the ability to adapt in real time. To solve this, the study introduces a morphing fluidic lens that can change shape on demand, giving engineers much greater control over how and where acoustic energy is directed while maintaining high acoustic resolution. In addition, a powerful holographic inverse design method called the Iterative Angular Spectrum Approach (IASA) is applied for the first time for elastic wave manipulation, overcoming the limitations of the conventional forward design methods. This technique helps create advanced materials known as elastic metasurfaces, which can fine-tune elastic waves for tasks like energy harvesting and structure health monitoring. Finally, the research takes a close look at how acoustic waves behave in soft, tissue-like materials—laying important groundwork for ultrasound haptics, a technology that lets people "feel" virtual objects without touching them. By identifying how certain wave modulation techniques reduce energy localization, a new solution is developed to sharpen tactile sensations while keeping the energy efficient and localized. Altogether, this work opens new possibilities for smarter, safer, and more responsive ultrasound systems across medicine, technology, and human-computer interaction.