Evaluating the Microwave Performance of Epidermal Electronics with Equivalent Transmission Line Modeling

Epidermal electronic systems, which conformally adhere to human skin, are a promising technology for wearable biomedical applications. Within these systems, the wireless components are made stretchable by translating solid traces into serpentine mesh patterns, which enable lateral spring-like mechanics. To ensure robust performance, there is a need to further study the impact of the serpentine mesh geometry and its stretching mechanics on microwave propagation. In this paper, we evaluate these impacts by modeling serpentine mesh traces in a microstrip system and extracting the corresponding effective transmission line parameters. The parameters are extracted by fitting full-wave results to an equivalent transmission line model. By demonstrating how the serpentine geometry and mechanics affect the power attenuation, electrical length, and impedance of microwave components, we provide a crucial step forward in the development of hiah-nerformance wireless wearable electronics.