On the field uniformity of reverberation chambers – a global sensitivity analysis study

Abstract

Purpose Global sensitivity analysis (SA) by means of Sobol’ indices enhanced with different surrogate modeling techniques is performed in this work. The purpose is to investigate the influence of measurement uncertainties and the environment characteristics themselves on the desired field uniformity in reverberation chambers (RCs). This yields an efficient apparatus for the stirring and chamber design process. Design/methodology/approach The technique of Sobol’ indices, as a candidate of global SA methods, is suitable for high fluctuations due to its robustness, which can be addressed to the stochastic nature of the RC environment. The aim of using surrogate modeling techniques is to compute the indices efficiently with a moderate number of required simulations. The powerfulness of this approach is introduced in a simple numerical example in which the physical phenomena can be identified more straightforwardly. Findings This method can provide useful knowledge in the lower frequency range, where the ideal properties of the electromagnetic field in RCs cannot be established, and the importance of the setup parameters can vary from configuration to configuration. In addition, it can serve as a basis for setup adaptation during parallelized electromagnetic compatibility tests, which would result in a more time- and cost-saving option in industrial applications in the future. Originality/value Despite the previous attempts, a profound investigation of multiple setup parameters is still a hot topic. The main contribution of this work is the extension of the application area of the method of Sobol’ indices to RCs, which has not been done so far.

Sensitivity analysis with various parameters in undermoded reverberation chambers

“…However, there is no unequivocal agreement for the lowest usable frequency (LUF), where the field is well-stirred, the overmoded condition applies; thus, the RC is capable of performing certain tests (Holloway et al, 2006). The most common thumb rules considered in this work are in accordance with the previous studies (Kenderes et al, 2023b;Kenderes et al, 2023c;Kenderes et al, 2023a). Besides, there exist improved considerations which reflect the spatial properties of the EM field more adequately.…”

“…The ranges of the input parameters are listed in Table 1. The denotations # TX ; Dxstirrer and DV stirrer stand for the elevation angle of the TX antenna, the displacement of the stirrer along the x-axis and the scaling factor of the stirrer volume, respectively, in Undermoded reverberation chambers accordance with Kenderes et al (2023c). In Figures 4 and 5, the parameters related to the TX antenna are marked in blue, and the red colour is associated with the stirrer-related ones.…”

“…In the SA studies, in accordance with the previous works (Kenderes et al, 2023a;Kenderes et al, 2023b;Kenderes et al, 2023c), Sobol' indices were used. The benefit of choosing this method is detailed in Kenderes et al (2023).…”

“…The stochastical perspective of the so-called kriging model appeared to be the most suitable. Therefore, it was used in Kenderes et al (2023b) and Kenderes et al (2023c). The kriging metamodel (Marelli and Sudret, 2014) constructs the model output as a realization of a Gaussian process, which can be described by the following equation:…”

“…Furthermore, the role of the stirring volume was investigated in a separate SA study. In Kenderes et al (2023c), additional parameters were considered such as the angles between the blades in a common Z-shaped design of the mechanical stirrer. A full-wave computational model was built, which was substituted by a black-box model to efficiently calculate the chosen SA measures.…”