Dual-polarized chipless humidity sensor tag

In this letter, a miniaturized, flexible and high data dense dual-polarized chipless radio frequency identification (RFID) tag is presented. The tag is designed within a minuscule footprint of 29 × 29 mm2 and has the ability to encode 38-bit data. The tag is analyzed for flexible substrates including Kapton® HN DuPont™ and HP photopaper. The humidity sensing phenomenon is demonstrated by mapping the tag design, using silver nano-particle based conductive ink on HP photopaper substrate. It is observed that with the increasing moisture, the humidity sensing behavior is exhibited in RF range of 4.1–17.76 GHz. The low-cost, bendable and directly printable humidity sensor tag can be deployed in a number of intelligent tracking applications

Polarization Insensitive Compact Chipless RFID Tag

This research article proposes a highly dense, inexpensive, flexible and compact 29 x 29 mm(2) chipless radio frequency identification (RFID) tag. The tag has a 38-bit data capacity, which indicates that it has the ability to label 238 number of different objects. The proposed RFID tag has a bar-shape slot/resonator based structure, which is energized by dual-polarized electromagnetic (EM) waves. Thus, portraying polarization insensitive nature of the tag. The radar cross-section (RCS) response of the proposed tag design is analyzed using different substrates, i.e., Rogers RT/duroid (R)/5880, Taconic (TLX-0), and Kapton (R) HN (DuPont (TM)). A comparative analysis is done, which reveal the changes observed in the RCS curve, as a result of using different substrates and radiators. Moreover, the effect on the RCS response of the tag is also examined, by bending the tag at different bent radii. The compactness and flexible nature of the tag makes it the best choice for Internet of things (IoT) based smart monitoring applications

Miniaturized humidity and temperature sensing RFID enabled tags

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 × 23 mm2. 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