Investigating the Impact of Antenna Directivity on Working Volume Equivalence in Reverberation Chambers Using Reconstructed Sensitivity Maps

In this paper, the equivalence of working volumes (WV) in reverberation chambers (RCs) is investigated by the regime of state-of-the-art sensitivity analysis (SA) techniques by inspecting the effect of changing configuration parameters to the field uniformity (FU) in a frequency-dependent study close to the lowest usable frequency (LUF). The Sobol'indices as SA measures are evaluated at each stirrer step and frequency. For efficient calculation, different state-of-the-art surrogate modeling techniques were utilized to substitute the full-wave simulation model depending on the characteristics of the WVs. The computational expenses of the problem are further reduced by using a decreased number of stirrer steps and frequencies, which are achieved by means of adaptive sampling techniques through Kriging interpolation. Furthermore, the size of the experimental design (ED) set, i.e., the number of different configurations is controlled by performing convergence studies. This method is able to reconstruct the 2D sensitivity map (SM) of the configuration parameters as functions of the stirrer steps and the frequency with a fewer number of samples. In this work, the effects of the directivity of the trasmitting (TX) antenna are investigated by evaluating the SM, while comparing the results obtained by antennas having different directivity properties.