A Wearable Backscatter System Featuring Concurrent RF Harvesting and Bidirectional Communication with Commodity BLE Transceivers

Emerging wearable medical sensors enabling real-time health monitoring have become increasingly important for personalized healthcare. Nearly all devices require wireless connectivity at low power to reduce size, weight, and maintenance costs (recharging or replacing the battery). Recent works in body channel communication (BCC), such as galvanic [1], magnetic resonance [2], and capacitive coupling [3], have demonstrated low power communication around human bodies, thanks to the reduced path loss. However, current BCC solutions rely on custom-designed transceivers (TRX) that are not built into commodity hardware (i.e., smartphones/smartwatches). To enable rapid deployment at scale with low cost, communication should ideally be compatible with existing infrastructure, such as WiFi and BLE. However, conventional WiFi or BLE TRXs require 10s to 100s of mW of active power; therefore, large/frequent recharged battery is still necessary.