Compact Multi-bits Chipless-RFID Curl Resonator Tag with Temperature Sensing Capability

This paper proposes a compact multi-bits chipless-RFID tag using fully printed resonators with dual performance of tagging and sensing temperature. Each bit is modelled as curl resonator coupled to microstrip line and is printed on metal-backed Rogers RO4003 substrate. A −10 dB attenuation level is obtained with narrow bandwidth and power reflection of −3.2 dB. The effect of the tag dimensions on the transmission coefficient response is introduced. The resonance frequency of each bit is controlled via controlling the curl arm’s length. The multi-bits RFID tag is modelled using multi-curl resonators arranged next to microstrip line with different arm lengths. A multi-bits chipless-RFID tags with 3-bits, 6-bits and 12-bits are designed in the 3–7 GHz frequency band. The dimensions of 6-bits code are 60×17 mm2 and for 12-bits code are 29.75×34 mm2. A temperature sensing capability is achieved via integrated Stanyl polyamide material with the curl resonator. The first bit is used for temperature sensing while the other bits are used for data encoding. The proposed chipless-RFID tags are simulated using finite element method (FEM) and finite integral technique (FIT).