Stretchable serpentine microwave devices for next-generation wearable systems
Abstract/Contents
- Abstract
- Over recent years, the use of patterned serpentine geometries in stretchable wearable electronics has attracted significant attention, especially for health monitoring in fitness and biomedical applications. While stretchable serpentine systems have been demonstrated for direct-current (DC) and low-frequency applications, there is a need to further study the influence of the serpentine geometry on high-frequency characteristics, to avoid potential parasitic effects or impedance issues. Furthermore, the impact of the serpentine stretching mechanics on wireless performance remains relatively unexplored. This work describes a general strategy for producing stretchable microwave components in which rigid, planar metallic structures are deconstructed into stretchable mesh geometries based on subwavelength-scale unit cells. The impact of this conversion strategy on microwave performance is examined for serpentine meshed transmission lines and antennas. Observations of surface current propagation and antenna radiation efficiency indicate an inherent trade-off between mechanical stretchability and microwave performance. Using the insight gained from investigating the performance impacts on transmission lines and antennas, the serpentine conversion strategy is then applied to produce a stretchable electromagnetic device for biomedical wireless power transfer in the electromagnetic midfield. A stretchable microwave phased surface is designed and fabricated to transmit a focused electromagnetic field into the human body to wirelessly power a miniature biomedical implant. Its performance with stretching is characterized in an experimental setup, and results indicate that with proper design, the serpentine phased surface can achieve comparable performance to its solid counterpart. To ensure optimal design decisions for future stretchable microwave systems, a general methodology is developed to model the microwave performance of various serpentine geometries. Serpentine designs are implemented in a microstrip transmission line system, and the effective transmission line parameters are extracted by fitting results to an equivalent transmission line model. This methodology is utilized to benchmark the serpentine microwave performance relative to alternative materials approaches. It is also useful for assessing the performance impacts of changes to the serpentine design. From these demonstrations, it is clear that the proposed methodology is highly useful for evaluating and improving the performance of future wearable systems.
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 | 2018; ©2018 |
| Publication date | 2018; 2018 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Chang, Tammy |
|---|---|
| Degree supervisor | Fan, Jonathan Albert |
| Degree supervisor | Lee, Thomas H, 1959- |
| Thesis advisor | Fan, Jonathan Albert |
| Thesis advisor | Lee, Thomas H, 1959- |
| Thesis advisor | Arbabian, Amin |
| Degree committee member | Arbabian, Amin |
| Associated with | Stanford University, Department of Electrical Engineering. |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Tammy Chang. |
|---|---|
| Note | Submitted to the Department of Electrical Engineering. |
| Thesis | Thesis Ph.D. Stanford University 2018. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2018 by Tammy Chang
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
Also listed in
Loading usage metrics...