Effiziente Simulationsmethoden für die Optimierung von komplexen Fahrzeugantennensystemen (Volume 19) (English shop)

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This work investigates antennas integrated into the window panes of automobiles. The investigations are carried out both by simulation and by measurement. Mechanical requirements arising from high mobility, long service life and, not least, aesthetic considerations severely restrict the available installation space and the possible design of the antennas, which places particular demands on the antenna design. Furthermore, the vehicle dimensions are of the same order of magnitude as the wavelengths of the frequency range from 50 to 500 MHz examined here, so that the vehicle itself has a major influence on the reception properties of the antenna. Simulation methods specifically optimised for this application are therefore required, which make it possible to take the complete vehicle into account in the computation.

The Method of Moments (MoM) for solving the electric field integral equations (EFIE) and its suitability for simulating the complete vehicle are explained. A method for the numerical electromagnetic simulation of car antennas is developed on the basis of the Method of Moments. Here, the field sources are described by magnetic surface currents impressed in the apertures. This method is combined with the Uniform Geometrical Theory of Diffraction (UTD) to form a hybrid method that enables efficient computations for certain types of vehicle antennas.

When modelling the highly complex overall system of antenna and vehicle, simplifications must always be made in consideration of computation time and for reasons of data availability. Systematic investigations of the influence of these simplifications are presented, which extend the existing modelling guidelines. In the course of improving the simplified model, the influence of the measurement environment on the measurement results used to verify the simulation is also addressed. The assumptions made to date regarding the conductivity of the ground are systematically investigated and examined for their validity in the field of vehicle antenna measurements. Corresponding recommendations for their correct consideration in the simulation are given.