Marco Rozgic

Simulation based analysis of field correlation and ergodicity of a reverberation chamber

The electromagnetic fields in an electromagnetic reverberation chamber (ERC) with a rotating mode stirrer are numerically determined for each stirrer position via a finite element (FE) simulation. With these results both a correlation analysis according to the present engineering standard is performed and the spatial variation of the field averaged over all stirrer positions is computed. Thus, it is studied how far the notions of correlation and ergodicity of the chamber are related. With an efficient FE simulation at hand, further studies comprising loaded chambers and geometry optimization for electromagnetic compatibility testing will become possible.

Constructive adjustment of characteristic parameters of a mode-stirred reverberation chamber for EMC tests and power spectroscopy

The purpose of this work is to develop a knowledge base which allows for the assessment of the influence of individual construction parameters on a mode stirred chambers performance in its particular area of application. With this knowledge, it would be possible to adapt a chamber for a particular purpose, e.g. to use the chamber for electromagnetic compatibility test procedures or for power spectroscopic measurements. The scattering parameters as well as the field strength and the distribution of the electric field are employed to quantify the influencing construction parameters of the chamber. In addition, a concept for a 3D positioning system is presented which can be used to accurately measure the electric field in the chamber. This is necessary in order to be able to make statistical statements about the electric field distribution.

Finite element simulation of the frequency-dependent polarization of biological cells

The impact of electromagnetic fields on biological tissue is increasingly gaining relevance for electromagnetic compatibility considerations. To estimate such effects, the determination of the electromagnetic exposition on the cellular level is essential. Hence, a new method for the finite element simulation of biological cells in electrolyte solution based on the electro-quasistatic approximation to Maxwells equations is presented here. By non-overlapping iterative domain decomposition (IDD), a more efficient and accurate incorporation of surface charge relaxation on material interfaces is achieved than by former methods. IDD does not only lead to an efficient consideration of the interface coupling of electrical flux- and current densities, but also overcomes numerical problems related to size differences of individual cell components. A completely parallel treatment of the resulting subdomains will enable the simulation of large cell systems in the future. The approach is validated in the case of a time-harmonic external field. Further, numerical errors and convergence properties are analyzed.