Realistic Modelling Of Chipless RFID Based Multi-Sensor Tag

Abstract

Radio Frequency Identification (RFID) is one of the leading supporting technologies for Internet-of-Things (IoT) allowing data from everyday objects to be collected and shared via internet. RFID technology was developed to overcome the short comings of the conventional optical object recognition methods like barcodes which required line-of-sight communication, human intervention, closer reading range and it could scan only one object at a time. RFID technology avoids all these limitations by providing a non-line-of-sight communication at a faster speed, greater reading range and without any physical contact, multiple objects can be detected remotely and simultaneously. Today, RFID finds vast applications in various sectors that include retail and logistics, healthcare, food and pharmaceutical industry, agriculture, transport, security, etc. for purposes like access control, inventory and asset tracking, parking, theft control, environmental monitoring, etc. Keeping in view the increasing demand of fast identification and tracking of objects without requiring direct line-of-sight, an RFID tag has been proposed in this research that has a compact dimension and offers a high data density. The reported tag is a chipless RFID based multi-sensor tag that can act both as a humidity sensor or a temperature sensor. The tag has a slot-resonator-based geometry and occupies a miniscule area of 2.4 cm2 with data transmission capacity of 29 bits. The tag has initially been designed using Rogers RT/duroid® 5880 which operates in the frequency range of 5.48 – 28.87 GHz. The same tag has been optimized for four other rigid and flexible substrates that include Rogers RT/duroid® 5870, Taconic TLX-0 Kapton®HN and PET (Polyethylene Terephthalate) using copper, Aluminium and silver nano-particle-based ink as radiators. Integration of sensing feature within the same tag has been achieved by the deployment of a thin film of Kapton®HN over the longest slot of the tag for moisture sensing, and filling of Stanyl® Polyamide in the longest slot for temperature sensing. The sensing behavior of the tag is exhibited in the Most Significant Bit (MSB) in the microwave response of the tag. The novelty of the tag lies in its ability to tag 229= 536,870,912 distinct objects, its flexibility, printability, high code density of 12.08 bits/cm2, and sensing property.