A wireless, wearable, battery-free multi-sensory system is essential for continuous, non-invasive real-time monitoring of multiple physiological parameters, enabling seamless, discreet healthcare. The main bottleneck in developing such systems lies in achieving low power consumption to enable battery-free operation, while maintaining reliable, high-frequency data acquisition and efficient wireless communication with a skin-impedance-matched antenna within a compact, wearable form factor. To overcome this, we integrate energy-harvesting technologies with high-precision multiple sensors and a flexible, skin-compatible antenna system into a single platform, enabling battery-free operation with efficient data transmission and reception. Our multi-sensory system experimentally demonstrates successful skin-mountable monitoring of ECG, SpO 2 , and temperature at a sampling rate of 70 Hz, with data wirelessly transmitted via Bluetooth Low Energy, all powered by a radio-frequency energy-harvesting antenna. Beyond personal health tracking, this technology also holds great potential for remote patient monitoring in chronic disease management, empowering healthcare providers with continuous access to real-time patient data for timely and uninterrupted data acquisition. Typically, health monitoring systems depend on separate hardware for each physiological signal—such as electrocardiogram, pulse oximetry, and temperature—which requires bulky setups with complex wiring, limiting their practicality for wearable and continuous use. These limitations significantly hinder proactive and long-term monitoring beyond clinical settings. Here, a fully integrated, skin-mountable multisensory patch designed for chest application is demonstrated. The system simultaneously acquires electrocardiogram (ECG), pulse oximetry, and temperature signals, powered sequentially via a battery-free near-field communication (NFC) antenna. Furthermore, high-frequency, noise-free data transmission is achieved through a skin-impedance-matched flexible Bluetooth antenna, ensuring seamless communication without compromising user comfort. This compact, wireless system makes it possible to monitor vital physiological parameters remotely and in real time, helping with early diagnosis, ongoing care, and preventive health tracking outside clinical environments. Fig. | Conceptual illustration of a battery-free, skin-mountable wearable patch. The system enables simultaneous energy harvesting and data transmission through an integrated flexible NFC and Bluetooth antenna. • Integration of Electrocardiogram, pulse oximetry, and temperature sensing into a single flexible and skin-conformal patch for comprehensive physiological monitoring. • Battery-free operation through sequential powering enabled by an embedded NFC antenna for wireless energy harvesting. • Flexible Bluetooth antenna matched to skin impedance for robust and noise-free wireless transmission in real-time. • Optimized system for short-range wireless data transfer (1–10 m), enabling real-time smartphone visualization and cloud connectivity. • Demonstration of consistent signal quality across ECG, SpO₂, and temperature, benchmarked against commercial devices.
Manjunath et al. (Sun,) studied this question.