In this study, a novel wideband near-coupled millimeter-wave microstrip array antenna is proposed,

specifically designed for 77-81 GHz medium and long-range automotive radar applications.The antenna array comprises

a microstrip line and series of rectangular and polygonal radiation units.These units are periodically distributed

on both sides of the microstrip line and separated by approximately half of the guiding wavelength.The rectangular

and polygonal radiation elements are designed to enhance excitation coupling.In addition, the impedance bandwidth

is widened and out-of-band frequency is suppressed.Different radiation elements and rectangular reflection

slots are matched to achieve the beam shaping effect and realize a flat shoulder radiation pattern.The normalized resistance

of the radiation unit is controlled by adjusting the interval between the radiation unit and microstrip line.At

the operating frequency range of 77-81 GHz, the gain of the array antenna exceeds 14 dBi, and the impedance bandwidth

reaches 7.47%(76.5-82.4 GHz).An actual example was processed and tested, and the accuracy of the design

was confirmed by simulations and actual measurements.