Study and Design of Wireless Patches for Biomedical Data Collection

Wearable biomedical systems are an enabling technology for continuous physiological monitoring and personalized healthcare. This dissertation presents the design and implementation of a compact, multi-sensor wearable biomedical patch powered and read wirelessly through Near Field Communication (NFC). The proposed system targets long-term monitoring while reducing user intervention by combining NFC-based energy harvesting and data communication with a rechargeable battery and USB-C charging. The wearable patch integrates multiple sensing modalities on a single ultra-low-power platform, including electrocardiography (ECG), electrode-based bioimpedance (BioZ), body temperature, inertial motion sensing, and acoustic signal acquisition. A dynamic NFC tag compliant with ISO15693 (NFC Type 5) is employed to enable backscatter communication and to harvest energy from an external reader. Power management is handled by a dedicated energy-harvesting PMIC, while system operation is optimized through duty-cycling strategies derived from physiological signal characteristics and power-budget analysis. Alternative sensing approaches, including RF dielectric sensing, are systematically evaluated to motivate the selection of electrode-based bioimpedance as the primary solution, highlighting robustness, repeatability, and suitability for realistic wearable conditions. The dissertation further details the complete schematic design, a four-layer PCB layout optimized for low-power operation and signal integrity, and mechanical integration considerations for wearable use. The proposed architecture demonstrates the feasibility of a multifunctional NFC-powered wearable patch and provides a validated design framework for future low-power biomedical wearable systems.