Method for measuring the resonant frequency of an RFID tag using a vector network analyzer and developed calibration and measuring boards

Calibration and measuring boards, made in the form of a special microstrip transmission line, have been developed. A wave resistance of the line is 50 Ohm. Each board has a connection to the «SMA-female» socket (50 Ohm resistance) for connection to the measuring device. Calibration boards are presented in three types: in the first board, there is no electrical connection between the transmission line conductors (open type), in the second board, the transmission line conductors at its end are connected by a conductive strip of copper by soldering (short type), in the last case, the electrodes are connected via a 50 Ohm resistor (load type). The measuring board is designed to be connected to the measuring device, for example, to a vector circuit analyzer. The proposed design of the boards can be used to measure the input impedance of antennas of various shapes or RFID chips using a vector circuit analyzer.