A Wideband Dual-Polarized Antenna and its Array With Electrically Downtilt Function for 5G Sub-6 GHz Communication Applications

A wideband dual-polarized antenna is proposed for 4G and 5G communication applications. The antenna element consists of a pair of opened-loop dipoles for dual-polarization and its three inherent resonant modes are shifted closer to form a wide bandwidth. With additional U-shaped slots etched around the feed point, the input impedance of the antenna element is matched to 50 Ohm. The fabricated antenna element operates from 1.8 to 4.0 GHz, having 75.9% (VSWR ≤ 2) impedance bandwidth and high port-to-port isolation (>25 dB). It also achieves a 67±1° beamwidth in H-plane and 68.7 ± 3.3° in V-plane with 8.5 ± 1 dBi gain across the supported bands. By using six antenna elements and designing RF phase shifting module (RFPSM) based on vector modulators, a six-element dual-polarized array with electrically downtilt is also fabricated and measured, realizing a peak gain of 16.8 dBi, a similar beamwidth in H-plane as single antenna element and an electrically downtilt in V-plane from 0° to 12° which is preferred in communication applications. This antenna array could be used for future 5G communication and other applications.