RFID Tag Antennas for Medical Applications

Abstract

The modern times are witnessing an unparallel impact of the advancement in the field of information technology on the overall medical care. However, there is still strong around the globe desire to further raise the healthcare standards. Consequently, the research community is pushed to strive for efficient and inexpensive means of automating the healthcare processes. Radio frequency identification (RFID) tags capable of integrating sensing, data storage and communication functionalities in one unit are pivotal for such automation. The present thesis, a small step towards digitalizing the healthcare, explores the utilization of RFID tags for improving the direct (patient) and indirect (non-patient) care processes. Wireless body-centric communication systems, providing a wireless and maintenancefree link between the human body and the surrounding, are the linchpin of the modernday personalized healthcare applications. Antennas are as pertinent to this direct care system as the eyes and ears are to the human body. The core of the research thesis is the design of efficient body-centric RFID tag antennas to boost the wireless healthcare applications. The antennas operate in the microwave band (2.4–2.48 GHz) that is in line with the high data rate requirements of the healthcare processes. In the course of the research work, a wearable antenna for off-body communication and an implantable antenna for in-body communication are designed and tested. The concerned body organ in both the cases is the human arm. The dielectric behavior of the human arm is integrated into simulations through a three-layered numerical phantom, whereas practical measurements utilize a non-homogeneous tissue-mimicking gel phantom. The proposed tag antennas fulfill the required attributes such as low-cost, low profile, miniature and biocompatible, along with countering the dielectric challenges of the human body. The wearable antenna needs to be immune to the on-body impedance detuning and radiation efficiency degradation. On the other hand, implanted antenna should have sufficient gain to establish the in-body wireless communication link. These challenges are the primary focus, as well as the contribution of the thesis. The thesis also highlights the design of inexpensive chipless RFID tags that finds scope in monitoring and management of low-cost medical inventory items (indirect care). The vi i tags encode data into the frequency domain using multi-resonant structures. A broad frequency spectrum is utilized to achieve high data capacity. The integrated broadband transmitting and receiving antennas enhances the read range of the tag. The proposed chipless tag is a useful contribution to facilitate the vision of broad scale deployment of RFID in healthcare systems.