Variability and Confidence Intervals of the Power Measured in a Reverberation Chamber

The relative variance (or variability) of the average power measured in a reverberation chamber is derived. It is found to be a function of the average number of modes overlapping in the average modal bandwidth found at the working frequency. The model can predict the average-power variance from under- to over-moded regimes. Good agreement with experimental and simulation data is obtained. Confidence intervals of the estimate of the average-power variability are computed for different chamber regimes and a varying number of independent stirrer positions.