Planar Antenna Array at D-Band Fed By Rectangular Waveguide for Future Automotive Radar Systems

Planar antennas are being used in frequencies up to 77 GHz for automotive radar because of their low profile and low-cost manufacturing. Also because of their flexibility when building phased and conformal arrays. In this paper a planar antenna around 140 GHz for the possible next generation of automotive radar is developed. This high frequency can provide narrower beams and better angular resolutions than the current sensor antennas. The structure is designed using a 3D electromagnetic simulator and is fabricated on a commercially available substrate. The fabrication consist of a common photolitography process which yields a very low-cost concept. In addition, this antenna can help to characterize the channel with planar systems, so the capabilities and limits of this technological approach can be tested. Experimental measurements were performed showing a gain of about 11 dBi and a return loss better than -10 dB over a band of 2 GHz.