[Back]

G. Artner, R. Langwieser, C. Mecklenbräuker:
"Antenna Efficiency Reduction Due to Carbon-Fiber Car Roofs";
Talk: Arbeitsgemeinschaft Hochfrequenztechnik der ÖFG, 3rd Workshop, Wien; 09-29-2015 - 09-30-2015.

Carbon fiber reinforced plastics (CFRP) are composite materials, which are used as construction material for aircraft, boat and car chassis. Due to their fiber structure the mechanical and electrical properties of CFRP are in general anisotropic.
The availability of a large conductive plane, such as an airplane hull or car roof, encourages the application of ground plane antennas. For intelligent transportation systems (IEEE 802.11p) the frequency band from 5.85 to 5.925 GHz already results in wavelengths (≈5 cm) close to the length of carbon fiber shreds used in industrial CFRP (around 3 cm). Therefore CFRP ground planes might influence the performance of those antennas.
A vehicular antenna module was mounted on the rear half of a CFRP car roof and an aluminium sheet. The radiation patterns show only small
differences between the CFRP roof and the aluminium sheet. Radiation efficiency was reduced by 10 % and 5 % (the antenna module contains two antennas for car-to-car communication).
One way to mitigate the reduced efficiency due to the CFRP roof is to superimpose a metal ground plane. It was investigated, if production with the laser direct structuring (LDS) process from LPKF would be favorable.

car roof, CFRP, CFC, carbon fiber, composites, antenna, shark-fin, automotive, vehicular