Design of Electromagnetic Road Markings for Implementing 77 GHz Millimeter-Wave Radar Sensing

Cameras and LiDAR are commonly employed for road marking detection in autonomous vehicles; however, both systems often struggle with weak environmental adaptability. A promising solution to this challenge is the implementation of millimeter-wave radar-based road marking sensing, given that millimeter-wave radar is one of the most widely used sensors in autonomous vehicles, known for its strong adaptability to various environments. However, the traditional road marking has a low RCS and is less effective in reflecting radar signals. Therefore, this study was designed an electromagnetic road marking comprising a metal reflector and a wave-transparent coating for radar signal reflection. Reflectors with various structures were developed and structural preference evaluations and size optimizations were conducted based on RCS simulations and test results. Various formulations of wave-transparent coatings were proposed, with the optimal formulation identified through mechanical property tests and electromagnetic wave power decay assessments. Finally, the electromagnetic road markings were prepared and tested using 77 GHz imaging radar for perception evaluation.