Theoretical Considerations about the Determination of Statistically Independent Stirrer Position of Mode-Stirred Chambers

This paper describes a possibility to simulate correlated boundary conditions inside a reverberation chamber and to analyze them regarding their autocorrelation function. Therefore a modified numerical plane wave representation is used. An important result is that the classical 1 / e-criterion overestimates the number of independent tuner positions by a factor of 2.5 to 3. Moreover the autocorrelation function varies heavily between simulations with same parameters and so the number of independent tuner positions as well. This effect is also known from measurements. With suitable averaging it can be shown that the number of independent tuner positions does not depend on the measurand (received power, field strength, transmission line current). If not only one measurand, but a whole distribution is used to analyze the tuner efficiency, then the fluctuation range decreases and the reliability of approximating the independent tuner positions increases significantly.