Extending Near Field Communication Range for Ultra-Dense Internet of Things

The advent of 6G wireless systems promises a digital world that blends physical and virtual elements, revolutionizing our interaction with the physical environment. A critical step towards this digital world is the creation of digital twins of physical systems and objects. The Internet of Things (IoT) plays an important role in connecting and monitoring these physical entities. However, connecting all objects in our daily life is challenging due to high density and large number of devices. Near Field Communication (NFC), utilizing High Frequency (HF) band signals, emerges as a promising solution. NFC has a short communication range and high penetration efficiency, with a reliable wireless channel that does not compete for spectrum with typical cellular and local area networks. Nevertheless, its extremely short range limits its use in autonomous IoT applications. This paper explores two techniques to extend NFC’s communication range and reliability: the use of high-quality factor transmit/receive coils and high-quality factor relay coils. Additionally, the effect of tag coil coupling in a multi-tag IoT environment is examined. Analytical models are developed to evaluate these approaches, and the results are validated using COMSOL Multiphysics. The findings demonstrate a significant increase in NFC’s communication range, i.e., up to 0.9 – 1.3 m for 1 – 10 W transmit power, making it suitable for ultra-dense battery-free IoT operations.