Miniaturized humidity and temperature sensing RFID enabled tags

Abstract

A compact 27-bit linearly polarized chipless radio frequency identification tag is presented in this research. The proposed tag is designed with an overall tag dimension of 23 3 23 mm 2 . The tag comprises of metallic (copper) rings-based structure loaded with slots. These slots correspond to a particular sequence of bits. The circular tag is analysed using 2 different substrates, that is, Rogers RT/duroid/5870 and flexible Rogers RT/duroid/5880. The radar cross-section response of frequency signatured tag is analysed for humidity and temperature sensor designs. Humidity sensing is achieved by deploying a DuPont Kapton HN heat resistant sheet on the shortest slot of the tag, that is, the sensing slot. Temperature sensing is attained using Rogers RT/ duroid/5870 and Stanyl polyamide as a combined substrate. Hence, the miniaturized, robust, and flexible tag can be deployed over irregular surfaces for sensing purposes. K E Y W O R D Schipless tag, electromagnetic, flexibility, humidity sensor, temperature sensor | I NT ROD UCTI ONInternet of things (IoT) also known as ambient intelligence is an emerging technology. It ensures connectivity of physical and virtual objects to the internet at an unprecedented rate, thus, transforming traditional objects into smart ones. 1,2 This technology is an integral part of internet future, and it will interconnect uniquely identified embedded items through ubiquitous communication of physical objects. 3,4 IoT uses wireless and pervasive computing technologies to make objects intelligent. 1,5 The idea of IoT can be implemented using radio frequency identification (RFID) technology. RFID is a promising technology which has revolutionized automatic identification and wireless sensing of tagged objects. 6 RF waves are exchanged between a tag and reader using wireless transmission. RFID is a fairly handy technology because it facilitates non-line of sight communication which improves the tag's efficiency and provides longer reading range. [7][8][9] At the item level tracking, RFID technology is replacing optical barcodes. 7 The fabrication of microchip circuits is really expensive, and this sets a certain limitation on the manufacturing of RFID tags. This problem can be solved by excluding the microchip from the tag design. RFID tag without silicon chip is famous as chipless RFID tag. [10][11][12] Chipless tags have Int J RF Microw Comput Aided Eng. 2018;28:e21151.

High Sensitivity Passive Wireless Humidity Sensor Based on Polyvinyl Alcohol

“…It adopts MEGTRON6 substrate and L-shaped resonant unit, which has a simple structure but a large size. Similarly, in some literatures, the large size of humidity sensor causes some difficulties in the use process, such as 42 * 17 mm 2 [21], 29 * 29 mm 2 [22], 23 * 23 mm 2 [23]. It can be seen that the sensor will be developed in the direction of miniaturized and low profile in the future.…”

High capacity chipless RFID tags for biomass tracking application

“…• The tags in [8,[18][19][20][21][22][23] are large in size and result in low code density. • The tags in [22][23][24][25][26] have weak backscattered signatures and so are susceptible to disruption by noise, where the reader is unable to distinguish between data and background noise. • The angular stability, i.e., the ability of the reader to collect the data over a range of angles of incidence to the tag was discussed only in [27].…”

Using a hybrid encoding method based on the hexagonal resonators to increase the coding capacity of chipless RFID tags

“…Different configurations have been used to design chipless RFID tags. The design presented in Reference 36 used arc slots, each resonating at a specific frequency (style 1). Style 0 in this design was obtained by removing or truncating a slot.…”