Analysis of Calibration-Free Detection Techniques for Frequency-Coded Chipless RFID

In this article, two calibration-free detection techniques including temporal separation detection and dual-polarized interrogation are analyzed for chipless radio frequency identification (RFID), and the design guidelines to improve the detection reliability are proposed. The two techniques aim to obtain electromagnetic signatures without measuring the response of clutter, removing the limitation on the evaluation of radar cross section (RCS), which requires measuring the response of clutter yet is widely used in the literature. However, no research findings are available concerning the detection reliability, design complexity, and computational efforts for the two techniques. This study analyzes these calibration-free detection techniques in terms of online detection and off-line design process. Concerning online detection, the two techniques are implemented in the same frequency band (2.0-4.0 GHz) with data capacity of 8 bits. Sixteen IDs are sampled, and the associated tags are fabricated. Their detection reliability is tested as the function of read range in four environments. Concerning the off-line design process, the sensitivity of design parameters is evaluated for each technique. The performance of the two approaches is compared; furthermore, to improve the robustness in real-world applications, optimum arrangements for filtering, temporal windows, and sampling points are characterized.