Open/closed formed tem cell design and measurement of shielding effectiveness of planar materials

With rapidly developing technology, the need for electronic devices used in military and civilian applications to operate at the required performance and at the same time with as little exposure to external electromagnetic interference as possible, emerges as an important issue in terms of electromagnetic compatibility. The fact that electromagnetic compatibility is so important in the electronics world has brought to the agenda the issue of taking adequate and necessary precautions against electromagnetic interference. Shielding; It is a method used to prevent electromagnetic interference, and the introduction of small-sized shielding structures, which are frequently preferred due to their ease of use and cost-effectiveness, emerges as an important development point in this field. Within the scope of this study, firstly, the effect of angular changes of the bottom and top soil plates on the measurement sensitivity of flanged TEM (TEM-t) cells, which are created by using a single TEM cell in two identical parts, which adopt the method of shielding efficiency through conduction, was examined; Subsequently, the effect of the dimensional differences of the central plate (septum) of the TEM cell, which represents the live end of a transmission line, on the measurement accuracy is emphasized. CST Microwave Studio program was used in all these experiments, and the shielding effectiveness of these structures with different dimensional properties was examined under the same conditions. In the next stage, the structure with optimum dimensional properties obtained as a result of the simulation was produced using a three-dimensional printer. Plastic derived TEM cell samples were created using PLA material for three dimensional printing, and the obtained samples were coated using different conductive structures. The reflection and transmission charactersitics of the final coated product were measured by means of a Vector Network Analyzer, and theoretical and practical results were compared with each other. In the next stage, the TEM cell was divided into two planar (TEM-t) and the effect of planar materials placed in the intermediate region on the transmission line was investigated. Simulations were run for three different methods; in the first one, the cell was loaded up to halfway, excluding the septum, in the second one, the septum was fully loaded, and in the last one, the septum was included and the loading was done and the results were examined. The most suitable method was determined and the performance of the low-cost and high-performance TEM-t cell obtained when the material was loaded, i.e. the change in S-parameters, was examined. Thanks to this method, the selection of planar structures to be used as screen materials can be easily made by taking the observed change in S-parameters as reference.