Analysis of near-field coupling in UHF-RFID systems

Near-field coupling analysis of UHF RFID systems is addressed. Numerical full-wave simulations are used to quantify the coupling between realistic reader and tag antennas. An impedance matrix approach has been adopted to evaluate the power transfer efficiency as a function of the distance between the reader and tag antennas, in the whole UHF RFID frequency band (860–960 MHz).