RFID Tag Analysis Using an Equivalent Circuit

In this paper, we analyze one of the most common UHF RFID tag antenna structures, a T-matched dipole. We for the first time derive the closed-form solutions for the resonant frequencies of tag sensitivity and backscatter responses as functions of tag equivalent circuit parameters. We apply our general analysis to a 70 mm x 14 mm T-matched RFID tag with Monza R6 and show a good agreement between the model, the measurements, and the derived formulas.