Wideband Dual-Polarized End-Fire Slotted Horn Antenna with Tightly Coupled Dipole and Monopole Probe Arrays

In this work, we present a novel wideband dual-polarized end-fire array antenna for 5G mmWave applications. The antenna design combines a tightly coupled dipole array (TCDA) for horizontal polarization, and a tightly coupled monopole probe array (TCMPA) with a slotted metal horn for vertical polarization to achieve wideband operation. The slotted metal horn enhances the radiation and impedance matching of the TCMPA, and makes operation of both polarizations in the same aperture. Both the TCMPA and TCDA operate at 23.8‒42.3 GHz (< ‒10 dB for broadside radiation, fractional bandwidth=56 %) which covers n258 (24.25–27.5 GHz), n257 (26.5–29.5 GHz), n261 (27.5–28.35 GHz), and n260 (37–40 GHz) in frequency range 2 (FR 2) specified by 3GPP. This wideband operation can be made possible by incorporating the proposed polarization-selective reflectors which optimize the performance of both the TCMPA and TCDA. Under same phase excitation, simulated array gains of the vertical and horizontal polarizations manifest as 4‒8 dBi and 4.4‒8.2 dBi, respectively. When scanning up to 45° from the array axis, those are degraded to 4.6‒7.2 dBi and 4.6‒5.6 dBi, respectively. Experimental results, including the matching bandwidth, realized array gain, radiation pattern, were compared with simulated results and they were in good agreement. Finally, we highlighted the comparative advantages of our proposed array that operates in FR 2, compared with dual-polarized end-fire linear array antennas operating over wideband.