Minimizing Measurement Uncertainty
Application Notes
All measurements are subject to uncertainty, whether from the instrumentation being used to make the measurement, the item being measured, the engineer conducting the measurement, or the measurement environment. Perhaps one of the largest contributors to the total uncertainty for RF and microwave power measurements is mismatch uncertainty. It arises from an incomplete knowledge of the phase of the reflection coefficients of the source and load impedances, plus their interconnection. Because the mismatch term almost always predominates, it requires extra attention from the engineer who can use simple procedures to minimize its effect.