Wideband Radomes for Millimeter-Wave Automotive Radars

We demonstrate the efficacy of periodic corrugations, fabricated as part of the radar cover to serve the dual purpose of protecting the radar circuitry and maximizing transmission in millimeter-wave (mmW) automotive radars. A 2-D array of square-base pyramids engraved on the plastic radar cover was optimized to achieve minimum reflection for a wide range of incident angles, +/- 40 degrees, and across the operating frequency band of 76-81 GHz. More importantly, we present an alternative radome texture, namely, the inverse-pyramid corrugations, which results in improved structural integrity compared to the pyramidal corrugations. This novel inverse-pyramid radome structure is also much easier to manufacture and achieves similar performance as the more conventional pyramid structure. Both designs are shown to significantly reduce radar cover reflections, which is perhaps the most significant bottleneck in modern mmW automotive radar sensor performance.