Measurement and analysis of vehicle influences on the radiation pattern of SDARS-antennas

Satellite digital audio radio service (SDARS) require omnidirectional antennas on vehicles, which are defined by given specifications. This paper clearly shows differences between the antenna performance as measured in an anechoic chamber and as measured on the final mounting position on the vehicle. The vehicle environment mainly determines the radiation of the antenna and often causes a severe degradation, of course dependent of the mounting location on the vehicle.