Adjustable impedance matching network for RFID tag antenna test

An impedance matching network is proposed, which can be used for ultrahigh frequency(UHF) band radio frequency identification (RFID) tag antenna performance testing. By adjusting the inductance value of this network, it can achieve the impedance match in 860～960 MHz range between different RFID tag antennas and vector network analyzer coaxial probe, and this makes the problem that directly test tag antenna parameters by using the vector network analyzer become feasible. Using this matching network, some actual tag antennas characteristic parameters are measured by vector network analyzer. The feasibility of the matching network is verified by compared the measured results and the theoretical and simulation results which show good agreements.