High-Isolated Coupling-Grounded Patch Antenna Pair With Shared Radiator for the Application of 5G Mobile Terminals

We propose a coupling-grounded patch (CGP) antenna pair for sharing the same radiator with the high isolation performance, where the two feeding ports are connected through such shared radiator with very close distance of
$0.1 \lambda _{0}$
. More specifically, two coupling pins (C-pins) grounded on the symmetry plane of the radiator are shown to be capable of tuning the common mode (CM) impedance to be the same as the differential mode (DM) impedance, thus a very high isolation of such patch antenna pair is obtained. Both simulation and measurement results demonstrate that the isolation of the patch antenna pair could be greatly improved from the original 3 dB to approximately 25–50 dB in the N79 band (4.8–4.9 GHz). Furthermore, the extension to four-port antennas is also investigated. The proposed patch antenna pair with less occupied area provides significant promising application values for the multiple-input multiple-output (MIMO) systems, especially for the sophisticated fifth-generation (5G) mobile terminals.