Intra-Body Backscattering for Wearable Ring Sensor

Noor Mohammed, Robert Jackson, Sunghoon Lee, Jeremy Gummeson

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Keywords: Wireless power transfer, backscatter communication, human body communication (HBC), intra-body power transfer, intra-body communication.

TL;DR: This paper presents a novel human-body communication technology that enables capacitive intra-body backscatter (C-IBB) communication between a batteryless ring sensor and a wrist-worn transceiver.

Abstract: This paper presents a novel human-body communication technology that enables capacitive intra-body backscatter (C-IBB) communication between a batteryless ring sensor and a wrist-worn transceiver. C-IBB leverages the finite conductivity of human skin and air coupling capacitance to facilitate near-field communication (NFC) between wearable devices. The C-IBB system features a radio frequency energy harvester connected to an impedance-matched wearable electrode, which charges a capacitor. This energy storage capacitor powers an ultra-low-power microcontroller, enabling backscatter communication by modulating the electrode’s load impedance. In this work, we developed a modular heterodyne transceiver system and intra-body channel gain emulator. These tools optimize transceiver and tag systems for realistic channel gains tailored to specific electrode configurations. We validated the system’s performance on the human body, optimizing it for sensing applications in a wearable ring format. Our preliminary study reveals that the system supports a bit rate of 20.83 kbps with a bit error rate of 10⁻³ to 10⁻² and operates effectively within a range of 23 cm.

Track: 13. General sensing and systems

NominateReviewer: Sunghoon Ivan Lee

Submission Number: 10