A bound on wireless power transfer to subwavelength devices in the body
Abstract/Contents
- Abstract
- Wireless power transfer to medical devices in the body is desirable for removal of bulky energy storage components. Most existing power transfer systems are concep- tually based on coils linked by slowly varying magnetic fields (less than 10 MHz). These systems have many important capabilities, but they are poorly suited for tiny, millimeter-scale devices where extreme asymmetry between the source and the re- ceiver results in weak coupling. In general, system parameters such as operating frequency and the structure of source that optimizes efficiency should be determined based on the receiver structure and position, as well as the tissue property of the body. Although many researchers attempt to optimize the system through numerical electromagnetic simulations and experiments of specific source structures and operating frequencies, it remains unknown which design parameters yield the highest global efficiency. This dissertation instead analytically solves the problem. With a proper modeling of tissue, we prove that for a given receiver structure and position, there exists an upper bound on power transfer efficiency and a solution for the current distribution that achieves this bound. The bound on efficiency and the optimal current distribution are evaluated for various medical applications -- a cardiovascular device to sense and stimulate heart signals, a wireless endoscope in the small intestine, and a neurostimulator in the brain to record neural activity. Reminiscent of Shannon's channel capacity in information theory, this theory predicts that there is significant room for improvement in existing power transfer systems and facilitates the design of structures to approach this optimal bound. The design procedure of the wireless power delivery system for a given receive structure in the body is demonstrated. The theory is verified with both numerical simulation and experimental results.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2013 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Kim, Sanghoek |
|---|---|
| Associated with | Stanford University, Department of Electrical Engineering. |
| Primary advisor | Poon, Ada Shuk Yan |
| Thesis advisor | Poon, Ada Shuk Yan |
| Thesis advisor | Meng, Teresa H |
| Thesis advisor | Miller, D. A. B |
| Advisor | Meng, Teresa H |
| Advisor | Miller, D. A. B |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Sanghoek Kim. |
|---|---|
| Note | Submitted to the Department of Electrical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2013. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2013 by Sanghoek Kim
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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