Open/Closed Formed Tem Cell Design and Measurement of Shielding Effectiveness of Planar Materials
Özet
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
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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.
