Triband Antenna Array for FR1/FR2 5G NR Base Stations

This letter presents the concept and development of a novel triband base station antenna array for the two fifth-generation (5G) new radio frequency ranges, i.e., frequency range 1 (FR1) and frequency range 2 (FR2). The proposed array combines three different dipole-shaped antenna arrays, one designed for FR2 and two for FR1 standardized bands, aiming sectorial coverage, multiple-input–multiple-output (MIMO), and massive MIMO applications. Particularly, a total of 98 radiating elements implies 80, 16, and 2 antenna array elements for the 26 GHz band (N258 channel), 3.5 GHz band (N77 and N78 channels), and sub-GHz band (N20 and N28 channels), respectively. Experimental results, in accordance to ANSYS HFSS numerical simulations, demonstrate dual-polarization feature and the following bandwidths: 0.65–0.88, 2.76–4.2, and 24.9–27.8 GHz. Regarding the array radiation pattern and MIMO figures of merit, the coupling among the array adjacent elements is kept lower than
$-$
20 dB and envelope correlation coefficient lower than 0.005. Furthermore, all the array elements provide a beamwidth of approximately 60
$^{\circ }$
, cross polarization lower than
$-$
20 dB, and gain varying from 7 to 9.7 dBi over the 5G bands.