New research led by Penn State engineers is paving the way for wireless, wearable health monitoring devices that can collect and transfer information. (Credit: Huanyu Cheng)

Researchers are developing devices to explore the possibilities of wearable, flexible antennas. The team found that changing the geometry of the antenna changes its performance, allowing for movement while leaving the transmitter frequency unchanged.

The team created the flexible transmitter in layers. Building upon previous research, they fabricated a copper mesh with a pattern of overlapping, wavy lines. This mesh makes up the bottom layer, which touches the skin, and the top layer, which serves as the radiating element in the antenna. The top layer creates a double arch when compressed and stretches when pulled — and moves between these stages in an ordered set of steps. The structured process through which the antenna mesh arches, flattens and stretches improves the overall flexibility of the layer and reduces RF fluctuations between the antenna’s states.

The bottom mesh layer keeps radio signals from interacting with the skin. This implementation, beyond preventing tissue damage, avoids a loss of energy caused by tissue degrading the signal. The antenna’s ability to maintain a steady RF also allows the transmitter to collect energy from radio waves, potentially lowering energy consumption from outside sources.