Virtual development of automotive antennas printed on glass using a hybrid of method of moments and method of auxiliary sources

Measurements of the far field radiation pattern at the AUDI measurement test site are done by setting the device under test on a turn table on an open area test site (OATS). The OATS is limited to one elevation angle of about four degrees due to the transmitting antenna´s fixed position. The transmission factor between the fixed antenna and the antenna under test is measured continuously while rotating the turn table over the complete azimuth. Objects in close vicinity to the automotive antennas like the car body or ground can influence the antenna behaviour. Hence, accurate modelling of the environment of the investigated antenna should be provided. On one hand it is important to consider the maximum of details which can affect the antenna characteristics like the turn table and the ground. On the other hand, it should be ensured that all details are correctly interpreted by the simulation framework and that there are no restrictions due to the implemented algorithms in the modelling from the simulation tool. Great care should be taken when modelling a real ground which usually is approximated by the commonly used simulation frameworks. In this work, several minutiae for ground modelling are given which permit an accurate evaluation and development of antennas. Furthermore, investigation results concerning the influence of the glass curvature and the body shell on the antenna performance are presented.