Field Homogeneity and Isotropy Analysis of a Reverberation Chamber Equipped with a Pair of Hemispherical Diffractors

In order to analyze the possible improvement of field homogeneity and isotropy by two additional copper hemispheres mounted on the wall and floor of a reverberation chamber, the electric field strength has been measured at eight positions in the working volume of the chamber. The measurement has been carried out over wide frequency range using fast field sensors. The experimental results are analyzed in terms of the standard validation procedure for an empty reverberation chamber according to Annex B of the IEC 61000-4-21 as well as to the field anisotropy coefficients defined in Annex J of this standard. The results show that the copper hemispheres hardly improve the field uniformity and slightly lower the quality factor of the chamber.