A wireless reader for detecting frequency shift of passive sensors

Abstract

A body area sensor network (bodyNET) consists of wearable and implantable sensors to monitor human physiological signals. While passive disposable, chip-free, and batteryless sensors have been widely studied, benchtop equipment is still required for data collection, limiting usage to laboratory settings. Efficient integration of passive wearable and implantable sensors with dedicated compact readout circuitry is crucial for enabling data acquisition outside controlled laboratory environments. Here, we present a miniaturized, flexible wireless reader (WiRe) designed for frequency-shifting passive sensors, which also incorporates power harvesting capability. WiRe is compatible with a wide variety of passive sensors, offering a versatile platform for diverse medical applications. We deployed WiRe across various passive sensor platforms to track frequency shifts associated with biological signals. Our results show that WiRe uniquely combines power harvesting with a flexible, portable readout interface, enabling effective and non-invasive detection of even minor frequency shifts in a frequency sweep range of 1–8 MHz with 100 kHz resolution for both in vitro and in vivo experiments.