A Miniaturized Dual-Resonator-Based High-Capacity Chipless Radio Frequency Identification Tag Sensor

The chipless radio-frequency identification (RFID) sensor is a potential technology for future RFID-based sensing systems. A novel ultra-wideband and retransmission-method-based frequency-coded chipless RFID tag is presented in this letter. The footprint of the proposed RFID tag is reduced by incorporating spur-line spiral resonators along with the spiral resonators. These resonators are designed within and around the transmission line connecting two orthogonal ports of the dual-polarized monopole antenna operating in the transceiver mode. Initially, the patch antenna and the resonator circuits are optimized separately for the intended impedance bandwidth and frequency response, respectively, and are later integrated together to achieve the required performance. The operating range of the tag antenna is from 2 to 5.2 GHz. Furthermore, two prototypes of the proposed RFID tag with the 10-b code are fabricated and tested. The simulation and experimental results are found to be in good agreement, validating the proposed design.