Design and characterization of wireless implant systems with ultrasonic power and data links
Abstract/Contents
- Abstract
- Implantable medical devices (IMDs) provide precise physiological monitoring and effective treatment by directly interfacing with specific organs and pathways. Current implants generally use large batteries for power and long wires to reach locations of interest, which makes them bulky and invasive; as a result, they are typically reserved for last resort treatments only. Miniaturization of IMDs down to millimeter-sized or smaller can mitigate undesirable immune response and operate in deep tissue for more targeted treatments. In addition, many of the medical applications of these implant systems, like neuromodulation can benefit from wireless data communication and networking capability for adaptive therapy and further improve treatment efficacy in a closed-loop fashion. To address these challenges and enable next-generation miniaturized wireless implant systems, we utilize ultrasound (US) for wireless power and data communication with a network of implantable devices. US has several advantages for powering and communication to miniaturized IMDs because it offers superior transduction efficiency and energy focusing due to its millimeter (mm) wavelength, low tissue attenuation through the body, and high safety limit which allows more power to be delivered for medical applications demanding more power. To provide design insights and optimize the performance of wireless implant systems using US, we present an analytical framework for optimizing end-to-end US link efficiency from transmitters to receivers to enable IMDs scaled down to mm or sub-mm dimensions. Key design objectives and trade-offs are considered for various parameters including the operating frequency, the transmission depth, the size of the transmitter, the impedance and the aperture efficiency of the miniaturized receiver, and the interface between the receiver and the power recovery chain on the implant. The design considerations and modeling for miniaturized US receivers using piezoelectric materials are then examined to obtain efficient scaled receivers. With the understanding of optimizing link performance, a mm-sized proof-of-concept implant for simultaneous US wireless power and bi-directional communication is designed and discussed. The fully packaged implant measures just 2.6 x 6.5 x 1.8 mm3, and it is the first such mm-sized implant that is able to operate with more than 6 cm in tissue. Finally, the system functionality and the networking aspect of the wireless implant systems are demonstrated at a large depth of more than 6 cm in tissue or tissue phantom with the customized US transmitter array.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2019; ©2019 |
| Publication date | 2019; 2019 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Chang, Ting Chia |
|---|---|
| Degree supervisor | Arbabian, Amin |
| Thesis advisor | Arbabian, Amin |
| Thesis advisor | Khuri-Yakub, Butrus T, 1948- |
| Thesis advisor | Rivas-Davila, Juan |
| Degree committee member | Khuri-Yakub, Butrus T, 1948- |
| Degree committee member | Rivas-Davila, Juan |
| Associated with | Stanford University, Department of Electrical Engineering. |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Ting Chia Chang. |
|---|---|
| Note | Submitted to the Department of Electrical Engineering. |
| Thesis | Thesis Ph.D. Stanford University 2019. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2019 by Ting Chia Chang
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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