Chipless RFID Sensors for Bioimplants: A Comprehensive Review

RFID technology has boomed in the area of biomedical applications, particularly in wearable sensors and bioimplants. The placement of the tag externally or internally generates numerous challenges, such as the design procedure, fabrication method, and real-time testing, along with unique challenges specific to diagnosis and other on-body applications. This article presents a review of bioimplants for several on-body applications associated with RFID technologies and their impact on human tissue. Several fabrication methods are also discussed, with a focus on understanding flexible, conformal, and strong RFID devices. In light of the future of upcoming applications, this article also reviews transformative RFID-based solutions for wireless body area network and implantable uses. In addition, the review highlights the design and implant of prototype devices. In sum, the main focus of this article is all aspects of chipless RFID utilized in multiple places in the human body, beginning with limb sensing and tracking, which basically involves a prosthetic structural tag (PST) responsible for providing information about a prosthetic limb in space. Similarly, the ultrahigh-frequency (UHF) passive RFID implant gives information about the tag, which is placed in the limb, and the communication between the readers takes place without any physical contact. An alternative touch probe method that resonates at about 13.56 MHz improves the accuracy of the implant. Stent tags are discussed for cardiovascular systems. Other specific topics covered are body implants based on an organically modified ceramic technology (ORMOCER) substrate, myoelectric prostheses, fractal-based RFID implants for crack sensing, and the thermal effects of implants.