Differential RCS and sensitivity calculation of RFID tags with Software-Defined Radio

Performance evaluation of passive Radio Frequency IDentification (RFID) tags is a challenging task. In fact, tag performance depends on multiple factors such as the goodness of the conjugate matching between chip and antenna, the chip sensitivity, the strength and quality of the backscattered signal. Commercially available solutions for tag testing are very expensive and not totally flexible. In this work, we propose a novel approach for precise characterization of RFID tags based on Software-Defined Radio (SDR). We show how a cheap (below 1000$) and flexible SDR-based RFID reader can be turned into an accurate tool for measuring the tag sensitivity and differential radar cross-section. We test our platform by analyzing the performance of two built-in-lab tags: measurements show a strong agreement with theoretical and simulation results.