Chipless RFID Multisensory Tags—Trends, Strengths, Challenges, and Prospects: A Review

The concept of chipless radio frequency identification (CRFID) multiparameter tag sensors is fairly new and nowadays has gained importance among researchers for their ability to identify objects and sense multiple parameters at once without requiring integrated chips (ICs), onboard power sources, and active components. This article presents a comprehensive review of such tag sensors, emphasizing its current stage of development, performance comparisons, and existing research gaps. This study provides a detailed classification of resonator structures, identification (ID) and sensing mechanisms, sensing functions and factors, and smart/sensitive materials (SMs), establishing a new unified taxonomy. Furthermore, it provides details on the sensing mechanism and physics behind it, maps resonator types to their design principles with their sensing functions, alongside their corresponding smart/sensitive materials (SMs), and reveals their multiparameter decoupling and selectivity techniques. It also comments on the substrates used and the adopted printing process. A critical quantitative evaluation follows based on key ID [coding capacity (CC), spectral density (SD), and spatial density (SPD)] and sensing metrics [sensitivity, dynamic range (DR), and read range (RR)]. Finally, this article discusses current challenges such as limited CC, short RR, absence of dedicated readers and standards, and issues with selectivity and suggests future directions, including artificial intelligence (AI) integration and scalable deployment for the Internet of Things (IoT), smart logistics, environmental monitoring, and industrial automation.