Design of a Wide-Beam Microstrip Array Antenna for Automotive Radar Application

In this paper, a novel wide-beam microstrip patch array antenna is proposed for automotive radar applications. Different from the regular wide-beam antenna, which is designed to achieve the wide-beam unit radiation performance, the proposed array antenna introduces the coupled-mode technology of the microstrip antenna to design an inclined unit radiation beam. The array elements are arranged alternately and in opposite phases so that the unit radiation beams alternately point to two sides of the array. The wide-beam feature and the high gain performance are realized simultaneously by the array characteristics. The excellent beamwidth and antenna gain performance enable enormous application potential in automotive radar. An 8-unit prototype working at 24 GHz is designed and fabricated for automotive radar applications. Measured results show that the special design scheme extends the horizontal-plane half-power beamwidth (HPBW) to 140°, and the maximum antenna gain is over 10.5 dBi.