On the Possible Benefits of Inserting Metallic Diffractors to Improve Low Frequency Performance of Reverberation Chambers

This article deals with a controversial topic in the field of reverberation chambers which is the potential efficiency of inserting diffracting metallic objects in order to improve the performance of these so-called “chaotic” chambers at low frequency. Taking advantage of the accuracy of the “well-stirred condition” method, an extensive campaign of measurements helps to conclude on the absence of any undeniable effect of such diffracting objects. It is also demonstrated that the insertion of these objects modifies (slightly) the quality factor of the chamber. Therefore, the performance of a chamber having different chaoticity degree has to be compared with and without these objects for the same Q-factor, which requires small amount of absorbers to be inserted in the chamber having a lower chaoticity degree in order to compensate the metallic losses of these diffractors. Otherwise, a bias is introduced which can lead to draw erroneous conclusions on their effects.