Development of RF Based Energy Harvesting Module for Passive Sensing

This paper presents the development of a radio frequency (RF)-based energy harvesting module for passive sensing, enabling wearable devices for measuring human physiological parameters. A compact meandered antenna was designed in Ansys, HFSS software to harvest RF energy at an operating frequency of 915 MHz UHF region. An LC based impedance matching network was designed to match the impedance of an antenna with a single stage rectification circuit in ADS software. The harvesting module, which is the combination of antenna and rectification circuit was fabricated and tested with in-house developed low-cost photoplethysmography (PPG) sensor. The lab-scale results are observed to be promising in developing a compact full-scale passive wireless sensor for monitoring physiological parameters.