Design And Simulation Of Reverberation Chamber With Irregular Shape

As a kind of new type of EMC test site, compared with the traditional test site, reverberation chamber has the advantages of wide test frequency band, excellent repeatability and short testing time. Another obvious advantage is that in the case of the same test distance and the same radiating power, the magnitude of electric field generated by an antenna in a reverberation chamber is much higher than that in free space. Thus, reverberation chamber has gained more and more attention. Virtually reverberation chamber is a metal cavity with a stirrer in it, and has high Q factor. Usually, because of its complex electromagnetic field structure, we can not gain the accurate value by theoretical calculations. The construction cost of a large reverberation chamber is also expensive. Thus, before the construction of a practical reverberation chamber, commercial electromagnetic simulation software is usually used to simulate the reverberation chamber, including the chamber structure, stirrer shape, the location of the workspace and the position of the ventilation window, which provides guidance to the construction of the reverberation chamber. Recently, a large reverberation chamber is planned to be constructed in the Electromagnetic Compatibility Lab of Beijing Jiaotong University. Based on two different simulation models, the thesis uses business software CST to optimize various design parameters of reverberation chamber. Meanwhile, the paper determines the appropriate simulation model and design parameters by comparing simulation results with theoretical analysis. This research is a part of the project "Reverberation Chamber Manufacture and Calibration Test Method Research" which belongs to the basic scientific research business expenses of Beijing Jiaotong University (Project Number:2011JBM207).First, the operating principle, basic structure, some important parameters, the application of reverberation chamber in the Electromagnetic Compatibility (EMC)Testing and the choice of Electromagnetic simulation software were introduced in the thesis. Then a regulate rectangular reverberation chamber model was constructed. The simulation results indicated that such reverberation chamber can fulfill the requirement of field uniformity of the standard IEC61000-4-21. The simulation results also indicated that the groove in the top of the reverberation chamber may influence the field uniformity in a certain extent. Based on the simulation results, the design parameter of the reverberation chamber, such as the reverberation chamber shape, the shape and size of stirrer, workspace and field uniformity of the reverberation chamber, were optimized.The thesis also studies the influence of loading position on the reverberation chamber performance. In most of the EMC tests, some loading inside the reverberation chamber are required. Nowadays, research about the loading of reverberation chamber is very limited. In the fourth chapter of this thesis, specific urethane absorber and ventilation window were used to load the reverberation chamber. The simulation results indicated that the location of absorber would influence the reverberation chamber function. In order to make the simulation more close to the practice, simulation model should use the actual metal wall instead of boundary conditions. From the simulation results, the influence of loading position on the field uniformity and field strength in the reverberation chamber was verified.