Characterization of Vehicle Penetration Loss at wireless communication frequencies

This paper presents the characterization of Vehicle Penetration Loss (VPL) at wireless communication frequencies up to 6 GHz. VPL is evaluated both empirically and numerically exploiting different automotive window coatings. Ultra-wideband (UWB) radio channel measurements were performed for the frequency range of 0.6-6.0 GHz inside an industrial facility employing a modern hatchback passenger car. Several realistic measurement scenarios were considered to obtain large measurement data sets that were post-processed to analyse directional penetration loss and channel delay characteristics. Measured average VPL was estimated to 3 dB for no window coating, 6.6 dB for commercial window film and 20.7 dB for windows covered with Aluminium metal foil. Full-wave numerical simulations based on finite-difference time-domain (FDTD) method were carried out at discrete frequencies of 900 and 1200 MHz for the assessment of VPL. The measured and simulated results were found in close proximity of each other. The results imply that the use of metallized automotive films can adversely affect the communication of radio signals into vehicles.