Isotropy study for over-the-Air measurements in a loaded reverberation chamber

We performed a field isotropy study based on the reverberation chamber transfer function for three different reverberation chamber configurations. Guidance for reducing the anisotropy based on the polarization-balanced antenna is also provided. We show that chamber isotropy is strongly influenced by loading such that an unloaded chamber can be considered as an isotropic environment, while a loaded chamber is more-or-less anisotropic depending on the amount of loading present. The loading of the chamber is crucial for wireless tests involving modulated signals. Its purpose is to create a flat channel, which enables successful demodulation of the signal without distortion. Consequently, understanding this effect is important in quantifying measurement uncertainty in loaded conditions.