A novel fabrication process for printed antennas integrated in polymer multi-layer car body panels

The complete fabrication process for the construction of printed millimeter-wave antennas integrated in plastic multi-layer car body panels is presented. Starting from material characteristics and fixed parameters obtained by the investigation of single process steps, the design of microstrip patch antennas at 24 GHz will be demonstrated. The fabrication is based on the hot embossing technology for the metallization of a polymer film used as antenna substrate. The antenna feed is realized by laser processing the ground plane, drilling the substrate and via connecting to the back side. The antenna is embedded within the plastic multi-layer structure by laminating a paint foil and reinforcing the part by back injection molding. The comparison between simulation and measurement results gives information about the realizability of plastic integrated millimeter-wave antennas and criteria for future design revisions. Far-reaching potentials of this process are associated with the construction of conformal integrated antenna arrays for automotive radar applications.