A reverberation chamber (RC) is a fully metallic enclosure widely used in various telecommunication applications an‎d testing environments. It serves as a versatile facility in fields such as antenna measurements, microwave engineering, electromagnetic compatibility (EMC), an‎d material characterization. By injecting electromagnetic energy into the chamber, a complex field environment is generated through resonant modes an‎d multiple reflections from the chamber walls. In this thesis, a comprehensive study on the optimal design parameters of reverberation chambers is presented. First, based on the intended application of the RC, the numerical methods required for RC simulation—particularly the NGF simplification method with high accuracy—are investigated. Subsequently, the design an‎d simulation of the RTS60 reverberation chamber are carried out. This work analyzes the effects of stirrers, chamber materials an‎d coatings, an‎d various loadings on the performance of the RTS60 reverberation chamber. Different stirrer configurations are compared, an‎d an optimal model is proposed. The quality factor (Q-factor) is measured using the four-point frequency method across 50 stirrer positions of the RTS60 chamber. By determining the Q-factor at 25 frequency points, the number of excited modes at each frequency is identified. Furthermore, the impact of stirrer arrangement on the generation of independent modes—crucial for achieving field uniformity—is investigated. The field strength an‎d number of independent modes in the RTS60 chamber are measured at 25 frequency points in the 250–900 MHz range for three stirrer configurations (50, 100, an‎d 380 steps). The autocorrelation coefficient, which reflects the degree of independence among excited modes, is also calculated. The main innovation of this thesis lies in transforming the RTS60 chamber’s application: from measuring the performance of MIMO devices an‎d wireless systems to supporting EMC testing by achieving enhanced field uniformity. This is accomplished through a novel approach involving antenna repositioning an‎d modified stirrer movement strategies, leading to significant improvements in field homogeneity. By performing both simulations an‎d experimental measurements of field uniformity an‎d comparing their results, the accuracy an‎d reliability of the simulations are validated. Notably, approximately 76,000 field intensity measurements were conducted for assessing field uniformity under various modes. An additional contribution of this research is the development of an efficient an‎d accurate design workflow an‎d flowchart for the simulation, design, an‎d construction of reverberation chambers with acceptable field uniformity across different lowest usable frequencies (LUFs) for EMC applications. Furthermore, two case studies involving the design an‎d simulation of reverberation chambers with Z-folded stirrer designs—based on the proposed methodology—are presented as practical examples.

ذاكرحسين فيروزه

ابوالقاسم زيدابادي نژاد , هادي علي اكبريان

محسن مداح علي , احمد بخت افروز , غلامرضا مرادي