On Excitation Periodicity in Continuously Stirred Reverberation Chambers

Reverberation Chambers (RC) provide a particularly robust environment for immunity tests by generating a statistically uniform field. The duration of such tests can be reduced for fast-responding equipment under test (EUT) by using fast, continuous stirring methods as opposed to the more common stepwise mode-tuned operation. However, continuous stirring methods, such as the Vibrating Intrinsic Reverberation Chamber (VIRC) or other flexible stirring systems, may experience periodicities in the mechanical excitation that limit the number of uncorrelated field distributions that can be generated. In contrast to the use of a conventional tuner, where the periodicity is defined by a full revolution, this is not always clear with non-rotating stirring systems. In this work the problems concerning periodicities in continuous stirring methods without rotating tuners are investigated. Using a textile flexible wall stirrer in a conventional chamber with rigid walls, possibilities are investigated to generate a maximum number of independent field distributions by breaking periodicities in the excitation.