Wideband and Ultrathin 2×2 Dipole Array Antenna for 5G mmWave Applications

This letter proposes a wideband (24–40 GHz) and ultrathin (0.76 mm) 2×2 dipole array antenna for fifth-generation (5G) millimeter-wave (mmWave) applications. For the ultrathin array antenna, it is a challenge to match the antenna input impedance because it usually has an extremely low value. Herein, a tightly coupled frequency selective surface is proposed to provide additional resonances, and a capacitively coupled feeding method and H-walls are employed to increase the bandwidth. Furthermore, consistent measurement results are guaranteed by vertical launch connectors, and the calibration process owing to the distortion at the connectors is briefly described. In addition, the cumulative distribution function of effective isotropically radiated power scan patterns is presented at various frequencies. Finally, the performance of the proposed array antenna is compared with those of state-of-the-art mmWave array antennas.