Co-designed millimeter-wave and sub-6GHz antenna for 5G smartphones

This letter proposes a co-designed millimeter-wave (mm-wave) and sub-6GHz antenna system. The antenna system consists of four 28GHz mm-wave arrays with reconfigurable radiation patterns and two sub-6GHz antennas fed with two corner capacitive coupling elements (CCEs). Each corner CCE is formed by the connected ground planes of two mm-wave arrays in the shared-aperture configuration. The two CCEs are separately matched to cover two sub-6GHz bands. Each mm-wave array consists of an active patch element and two parasitic patch elements loaded with PIN diodes, realizing 90-degree beam scanning range with two states of the PIN diodes. The measured results of the fabricated prototype show good agreement with the simulated ones. The prototyped mm-wave arrays cover the band 27.5-28.35GHz, and each achieves 90-degree beam scanning at 28GHz, with measured peak realized gain of 7.9 dBi. The CCE ports cover the two sub-6GHz bands of 0.79-0.96 GHz and 1.7-5GHz, with measured isolation of above 17dB and 20dB, respectively. The mm-wave band isolation is above 26dB.