Turn-Table Platform Stirring in Reverberation Chambers for OTA Applications

The reverberation chamber (RC) has been used for electromagnetic compatibility (EMC) tests and over-the-air (OTA) tests. The RC is a large metal cavity with one or more mechanical mode stirrers. The mode stirrers serve the purpose of changing the boundary conditions and interacting with the field so that the field in the RC is independent and identically distributed (i.i.d.) in the spatial domain. Due to the isotropic scattering property, the device under test (DUT) in the RC is fixed during the whole measurement procedure. This greatly reduces the measurement time compared with EMC tests in an anechoic chamber (AC), where the DUT must be measured over many rotation angles. However, the turn-table platform for the DUT is introduced back again for over-the-air (OTA) tests in the RC due to the more stringent uncertainty requirement. In this paper, the turn-table platform stirring is studied. Explanations of reintroducing the turn-table platform for OTA tests are given, and the significance of the turn-table platform stirring is stressed from the statistical point of view.