Inductive Compensation of High-Permittivity Coatings on Automobile Long-Range Radar Radomes

A theoretical and practical investigation of polymer composites including paint layers as radomes for automotive long-range radar systems operating at 76.5 GHz is carried out. The materials in focus of this research are metallic base paints with a high concentration of metal, and hence, a high dielectric constant. A multilayered free-space measurement technique is presented to derive the dielectric properties of coatings with a thickness of several micrometers. The impact of the paint layers on the radar performance are discussed in this paper, and a narrowband technique is presented to compensate the reflection effects of critical paints.