The rigorous characterization of ultrahigh-frequency passive radio-frequency identification (RFID) tags is a challenging but mandatory task. Indeed, tags are the most critical devices in RFID systems: their performance should be adequately good, although stringent requirements in terms of compactness, fabrication materials, and costs must be satisfied. Factors such as proper conjugate impedance matching between the chip and the antenna, chip sensitivity, and quality of the backscattered signal affect tag performance. Tag sensitivity and differential radar cross section (RCS) are the most significant metrics for tag characterization: they define the forward (from the reader to the tag) and the backward (from the tag to the reader) link reliability, respectively. Nevertheless, measurement of such metrics cannot be approached with conventional methods based on vector network analyzers or conventional RFID readers. Vice versa, commercially available measurement equipment and instrumentation are very expensive and not totally flexible.
At the EML2, a novel approach for thorough performance characterization of passive UHF RFID tags has been explored. To this end, we developed a very cheap (below $1000) and flexible tool based on software-defined radio (SDR), specifically on the open-source open-hardware GNUradio-USRP combination, which enables measurement of tag sensitivity and differential RCS. Exhaustive experimental campaigns have been carried out on several commercial and built-in-laboratory RFID tags. Achieved results demonstrating the flexibility, accuracy, and appropriateness of the proposed approach, along with more details about the SDR RFID test platform, can be retrieved from our publications listed below.
 L. Catarinucci, D. De Donno, M. Guadalupi, F. Ricciato, and L. Tarricone, “Performance Analysis of Passive UHF RFID Tags with GNU-Radio,” IEEE AP-S International Symposium, Spokane, WA, USA, July 2011.
 D. De Donno, L. Catarinucci, R. Colella, F. Ricciato, and L. Tarricone, “Differential RCS and Sensitivity Calculation of RFID Tags with Software-Defined Radio,” IEEE Radio and Wireless Symposium (RWS 2012), Santa Clara, CA, USA, January 2012.
 L. Catarinucci, D. De Donno, R. Colella, F. Ricciato, and L. Tarricone, “A Cost-Effective SDR Platform for Performance Characterization of RFID Tags,” IEEE Transactions on Instrumentation and Measurement, vol. 61, no. 4, pp. 903-911, 2012.
 D. De Donno, L. Catarinucci, R. Colella, and L. Tarricone, “Performance Evaluation of Passive UHF RFID Tags with Software-Defined Radio,” XIX RiNEm (Riunione Nazionale Elettromagnetismo), Roma, Italy, September 2012.