A Low-sidelobe Series-fed Microstrip Patch Antenna Array for 77 GHz Automotive Radar Applications

A low-sidelobe series-fed microstrip patch antenna array operating at 78 GHz is proposed for millimeter-wave automotive radar applications. The proposed array is mainly composed of 10 patch elements and an impedance transformer. A hybrid HFSS-MATLAB optimization method is adopted to quickly achieve the design goals. The simulated results show that the proposed antenna array achieves a -10 dB impedance bandwidth of 2.5 GHz from 76.9 to 79.4 GHz and a stable peak gain of 15-16.2 dBi. By optimizing the widths of the patches and the spacing between the elements simultaneously, the proposed antenna array achieves a low sidelobe level of -23.5 dB in the E-plane.