77 GHz center-fed differential microstrip antenna array

A differential microstrip antenna array design for millimeter-wave applications is presented. The antenna is fed by coupled microstrip lines, which facilitates the integration of antennas and differential circuits in RF-front systems. In this work, such an antenna array was designed for an autonomous cruise control application at 77 GHz. The antenna array has a bandwidth of 2 GHz at -10 dB return loss. The radiation patterns of co-polarization are stable over the bandwidth due to the center-fed structure. The 3 dB beam widths are 28 degrees and 78 degrees in the E-plane and the H-plane, respectively, and cross-polarization is very low. The measurement results are in good agreement with the simulation results.