Leakage error measurement of vector network analyser in National Institute of Metrology (Thailand)

Abstract

This study proposes a method to measure the leakage error of vector network analyser (VNA) in the National Institute of Metrology of Thailand (NIMT). To achieve this, a leakage model of the VNA is presented and analysed. Here, a programmable attenuator is represented as device under test (DUT) with an attenuation of A DUT and a fixed attenuator with an attenuation of A L is used to represent the radio frequency (RF) attenuation in air between the two ports of the VNA. The DUT is first analysed in terms of phase and attenuation as a function of frequency to represent any RF device with a constant insertion loss. Second, the phase shifter is adjusted to vary the phase of DUT. Also, the amplitude and phase of the leakage signal are measured as a function of (A L−A DUT) and they are compared with the mathematical model of leakage error. Finally, the maximum amplitude deviation of the leakage signal can be used as an uncertainty budget of leakage error of the VNA.