Leakage error measurement of Vector Network Analyzer in National Institute of Metrology (Thailand)

This paper proposes a method to measure the leakage error of Vector Network Analyzer (VNA) in the National Institute of Metrology, Thailand (NIMT). To achieve this, a leakage model of the VNA is present and analyzed. In the model, a programmable attenuator is used as the Device Under Test (DUT) with an attenuation of Adut and a fixed attenuator with an attenuation of AL is used to represent the RF attenuation in air between the two ports of the VNA. The DUT is initially characterized in terms of phase and attenuation as a function of frequency to represent any electronic device with a specific insertion loss. Then, the phase shifter is adjusted to change the phase of DUT and the amplitude and phase of the leakage signal are measured as a function of (Al-AduT) and compared with the mathematical model of leakage error. Finally, the maximum amplitude deviation of the leakage signal is used as a limit of leakage error of the VNA.