Tightly arranged orthogonal mode antenna for 5G MIMO mobile terminal

This letter presents an orthogonal mode 4-antenna system operating in the 3.5-GHz band (3.3-3.6 GHz) for the fifth-generation (5G) multiple-input multiple-output (MIMO) mobile device. The 4-antenna system is composed of 2 identical tightly arranged antenna pairs, and each pair is formed with an arrow-shaped monopole and a bended dipole with gap-coupled feeding. The tightly-arranged antenna pair is face-to-face arranged on the front and back side of the substrate and the distance between the center of the 2 elements is only 1 mm; however, they have good isolation (better than 10 dB) and diversity performance (envelope correlation coefficient better than 0.11) with the help of orthogonal mode. This configuration provides promising solution for compactness of the MIMO antenna in mobile phone. The prototype was fabricated and measured, and the measured results show good agreements with the simulated ones.