Chipless RFID Sensors for IoT-Based Healthcare Applications: A Review of State of the Art

Currently, there is a great demand for low-cost solutions in connected healthcare and real-time wireless patient monitoring remotely. Radio Frequency Identification (RFID) is a rapidly emerging wireless technique for remote data capturing utilized in multifarious applications such as healthcare, automated identification, object tracking, security and authentication, food packaging, and automobile tracking. The projected cost of conventional RFID technology hampers it from being used widely. Chipless RFID sensors with the Internet of Things (IoT) technology have the full potential to meet the requirements of the growing demand. With the development of present technologies, the IoT-based solutions are no longer a challenging vision that offers various potential benefits to today’s world, especially healthcare which is an encouraging field of IoT. The design and development of chipless sensors for health monitoring have gathered the attention of the researchers in last few years. This article provides a comprehensive review of chipless RFID sensors that play a vital role in cost-effective healthcare applications. The working principle of a chipless sensing system, fabrication techniques, and classifications of different chipless RFID sensors along with the smart sensing materials are highlighted. This paper throws light on numerous chipless RFID sensors for IoT-based healthcare applications including their challenges and future directions. In addition to that, a comparison table of recent developments in the area of IoT-based healthcare is prepared.