Extremely Low-Profile Wideband Patch Antennas Using Electric- and Magnetic-Coupling for 5G Mobile IoT Devices Application

The huge pressure of the metal bezels within Internet of Things (IoT) devices caused by massive antennas limits mobile antenna performance and further progress. Planar mobile patch antennas, which can be accommodated on IoT devices back covers that have a large available area, can relieve the bezel pressure. Based on the first two basic modes of the half-mode patch and by loading the parasitic half-mode patch using an electric/magnetic-coupling approach, each basic mode can be expanded into two modes with even- and odd-symmetrical distributions, producing four resonances and these resonances can be merged without radiation nulls. As a result, two wideband patch antennas with extremely low profiles are obtained. The widest mobile communication band of the 5G N77 [(3.3 to 4.2) GHz] is selected as the target. The designed E-/M-coupling patch antenna with the profile of 1.4 mm/1.0 mm (0.015λ_L/0.011λ_L) and with the size of 27.8 mm × 65 mm/35.2 mm × 50 mm shows the measured -6 dB impedance bandwidth of (3.14 to 4.33) GHz/(3.20 to 4.33) GHz and the minimum total efficiency of 60.3%/58.9%. As far as authors know, the proposed antennas have the lowest profile and highest antenna volume usage efficiency compared to other reported wideband patch antennas.