Design of a reverberation chamber from a shielded room

Abstract

Electromagnetic Compatibility (EMC) has become more important in the last half-century. The reason for this situation is sensors and similar sensitive electronic circuits, which are increasingly used in electronic systems. As a result of increasing electromagnetic pollution, electromagnetic interference (EMI) to systems has started to have very serious consequences. For this reason, some standards and restrictions have been introduced for almost all electronic products to be produced. These standards and restrictions describe the testing of products for electromagnetic compatibility. One of the test environments used in these tests is the reverberation chambers (RC). RCs are systems based on obtaining a uniform field level in a certain volume by stirring the electromagnetic waves emitted from a source in a closed room with the help of a stirrer. In this thesis, studies on the conversion of a screened room to an RC are included. Within the scope of this study, it was investigated whether the screened room is suitable for conversion to an RC and some preliminary measurements and simulations were made. Afterwards, the stirrer design, which is the most important part of an RC, was started. When the studies in the literature were examined, it was thought that the use of a Z-folded stirrer was appropriate. RC simulations were started with RC simulation with a vertically positioned stirrer, designed using ALTAIR FEKO electromagnetic analysis program. Subsequently, RC simulations with horizontally positioned 4-panel and 5-panel stirrers were performed. Then, an RC simulation with two stirrers was performed. In all these simulations, the position and angle of the antenna were kept constant and changes were made on the stirrer. Since the desired uniform field could not be obtained in this way, it was decided to follow a different plan. In the new simulations, the stirrer position was kept the same and changes were made on the location and angles of the antenna. As a result of the simulations, it was decided to produce the configuration that provides the desired uniform field. After the production and assembly of the stirrer were completed, the verification measurements of the RC were made. The matching of the measurements with the simulations showed the successful completion of the work. Although a difference was observed between the lowest usable frequencies (LUF), this was thought to be due to the simplified modelling of the RC. As a result, an RC that can be used in EMC tests was made for the first in Turkey. In the future, studies will continue to develop the established system.