Measurement of leakage signal in radio frequency or microwave systems

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

“…E L passing in this path is very small compared to E A and it can be omitted. The DUT and the phase shifter are completely covered by a thick aluminum foil with a thickness of 3-6 mm to prevent the leakages between both devices [21]. Therefore, E L and E A are now divided into two paths and they are finally combined at the power splitter 2 and down-converted to the VNA port 2 to analyse the S parameters.…”

“…Nevertheless, the leakage effects are still very difficult to detect due to the fact that they depend on both signal level and phase. As a result, their effects have to be carefully studied so that the desired signals can be correctly measured [19][20][21].…”

“…For the National Institute Metrology of Thailand (NIMT), the leakage (crosstalk) shall be measured via an experiment and it shall be included in the uncertainty budget of VNA measurement. As per the author's knowledge, there are many methods to measure the leakage [18][19][20][21]. Fig.…”

“…Recently, a modern attenuation measurement system is demonstrated. In this configuration, a phase shifter is used to replace the delay lines so that it is possible to accurately measure the amplitude of the leakage signal at any phases [21]. However, this method has some disadvantages for leakage signal measurement of VNA since the measured leakage signal is not the actual leakage (crosstalk) between two ports of VNA.…”

“…To overcome the disadvantages of unchangeable phase in the previous methods as shown in [18][19][20], our system includes a phase shifter to freely tune the phase of the received signals with a disadvantage that the phase shifter has to be wideband to be able to tune over the frequency range. Moreover, the external RF source and the external IF receiver as shown in [21] are now replaced by the built-in RF source and the external IF receiver of the VNA, respectively (traded off with the lower dynamic range and noise floor). This leads to the possibility to instantly and truly measure the leakage errors of the VNA and therefore the measured leakage in this method is more accurate.…”