A Compact Dual-Polarized Endfire Antenna Array for 5G Millimeter-Wave Terminal

This letter proposes a compact dual-polarized endfire antenna array for 5G millimeter-wave (mmWave) applications. The dual-polarized antenna unit is constructed by an open-ended substrate integrated waveguide (SIW) cavity for vertically polarized (VP) radiation and a broadband electric dipole for horizontally polarized (HP) radiation. By sharing the side walls of two neighboring SIW channels of the VP elements, the substrate integrated coaxial line feeding structure for the HP element is achieved, allowing a compact size of the final antenna array. To extend the bandwidth of the VP element, the quasi-TE
₁₁
mode of the cavity and the slot mode of the endfire aperture are adopted. A corresponding linear array with four units is designed and fabricated. The common −10 dB impedance bandwidth covers the range from 24.8 to 29.2 GHz. The maximum gain is 10.0 dBi for both polarizations, with an overlapped scanning coverage ranging from −41.5° to 45.5° at 27 GHz. The proposed design has a compact configuration, and a wide scanning range, which is an alternative for 5G mmWave terminal application.