Automotive Antenna Measurements in the Installed State Under Variable Boundary Conditions

Automotive antenna measurements are typically performed in an anechoic (free-space) or semi-anechoic (reflective ground) environment. Even though measurements under these conditions provide sufficient knowledge about antenna performance, the automotive industry often desires to evaluate installed automotive antennas under practical road conditions. This requires a combined approach to test and qualify vehicular antennas; however, facilities deploying variable boundary conditions for measurements are challenging to devise. Alternatively, numerical simulations can be used to perform such investigations; nevertheless, it is essential to verify such simulations through measurements. In the Virtual Road Simulation and Test Area (VISTA) of the Thuringian Center of Innovation in Mobility at the Technische Universität Ilmenau, a new approach to provide variable boundary conditions for antenna measurements is realized to evaluate the impact of different electromagnetic boundary conditions and to bridge the gap between numerical simulations and measurements. It consists of a modular and mechanically robust plastic frame carrying a customizable fabric substituting a ground plane. This paper presents and discusses the initial measurement results of a reference antenna and an installed automotive antenna performed over the conducting fabric. The convincingly good correlation of more than 74% between the measured data and numerical simulations shows the validity of the proposed method.