Electromagnetic Coupling-Based Wide-Beam Antenna Array for Automotive Forward Looking Radar

This paper presents a novel wide-beam antenna array for automotive radars. The antenna is designed based on microstrip lines and patches, combined with a proximity-coupled feeding method, achieving high radiation efficiency and a low quality factor. Measured results show that the antenna bandwidth is from 74.4-79.57 GHz, and the short-range detection angle is greater than 126.18 °. Moreover, the low-profile characteristic of the antenna allows it to be easily integrated with radio frequency (RF) chips. Its maximum gain is 14.26 dB, and the gain fluctuation within the impedance bandwidth is only 1.79 dB. Based on this antenna, a automotive forward-looking radar antenna array capable of simultaneous detection in medium and long ranges is designed. Measured results show that the long-range gain of the designed antenna array exceeds 20.62 dB, and the gain fluctuation within the operating frequency band is less than 1.2 dB. The measured results are in good agreement with the simulation results.