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

The concept of Chipless Radio Frequency IDentification (CRFID) multi-parameter tag-sensors is fairly new and nowadays has gained importance among the researchers for their ability to identify objects and sense multiple parameters at once without requiring integrated circuits (ICs), on-board power sources and active components. This paper 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) & sensing mechanisms, sensing functions & factors, and smart/sensitive materials (SMs), establishing a new unified taxonomy. Further, 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 SMs and reveals their multi-parameter decoupling and selectivity techniques. It also comments on the substrates used & the adopted printing process. A critical quantitative evaluation follows based on key ID (coding capacity, spectral and spatial density) and sensing metrics (sensitivity, dynamic range, and read range). Finally, the paper discusses current challenges such as limited coding capacity, short read range, absence of dedicated readers and standards, and issues with selectivity and suggests future directions including AI integration and scalable deployment for IoT, smart logistics, environmental monitoring, and industrial automation.