Co-design of Sub-6 GHz and mm-wave array antennas with metal frame for 5G mobile terminals

In this letter, a compact antenna module working at Sub-6 GHz and millimeter-wave (mm-wave) bands is presented for 5G mobile terminal applications. The module includes a long slot etched at the edge of the chassis ground and four short slots etched on the metal frame. By placing the two kinds of slots together, the short slots can work at the quarter-wavelength mode, thus the length of the short slots on the metal frame is merely 1.4 mm. It greatly reduces the risk of signal attenuation by users' touch. Experimental results show that the proposed design can provide MIMO function at 3.5 GHz band, and wide-angle beam steering function at 28 GHz band.