Low-cost Coaxial Slot Array Antenna for E-Band Automotive Corner Radar Applications Based on Gap Waveguide MLW Technology

This paper presents an E-band automotive radar antenna based on multilayer waveguide (MLW) technology. The electromagnetic fields propagate through a low-loss air-filled coaxial transmission line created by the stacking of three separate metal sheets. The fundamental antenna element consists of a single side-fed column composed of six in-line slots. An electromagnetic bandgap (EBG) structure is integrated along the transmission lines to mitigate the unwanted leakage resulting from small air gaps between the metal sheets. The fabrication of the prototype was realized by using a quick and cost-effective sheet metal manufacturing process, which has proven to be highly suitable for large-scale production. The measurement results for both radiation pattern and reflection coefficient agree with the corresponding simulations within the operating frequency band ranging from 76 to 81 GHz. The measurements results demonstrate a return loss better than 10 dB across the designated frequency band and the realized gain of the antenna is, on average, 11.5 dBi, with a beam width of 120 degrees in azimuth (E-plane) and 20 degrees in elevation (H-Plane).