Question: In OTA antenna performance conformance testing, if a different probe antenna cable is used for calibration and DUT measurement, how should the combined standard uncertainty of the insertion loss measurement be accounted for in the uncertainty budget?
Option 1: By assuming a Gaussian distribution and calculating the standard deviation from historical data.
Option 2: By ignoring it since the impact is negligible on overall antenna performance.
Option 3: By applying a fixed, predefined correction factor to all measurements.
Option 4: By using the maximum value of the insertion loss difference divided by 3, assuming a rectangular distribution.
Explanation: When different cables are used for calibration and DUT measurement in OTA antenna performance testing, the uncertainty from the insertion loss difference must be quantified. Given the assumption of a rectangular distribution for this uncertainty, the standard approach to calculate the standard uncertainty is to take the maximum value of the insertion loss difference and divide it by 3, providing a conservative estimate for a reliable conformance testing outcome.