Double-Layer Broadband and Wide Beam Microstrip Array Antenna For 79GHz Automotive Radar

A double-layer broadband and wide beam microstrip antenna is presented for 79GHz automotive radar. The antenna is composed of a microstrip line, a radiation patch and a parasitic patch. In addition, the radiation patch is fed by the microstrip line in the form of coupling feed. The parasitic patch on the top substrate is designed for wider band. Based on the double-layer elements, a 10-elements standing-wave linear array is constructed, which have broadband with 5 GHz from 76GHz to 81GHz. Besides, the array antenna can achieve a wide beam of 115° in the azimuth plane and a low side-lobe less than -20dB in the elevation plane.