Dual-feed Orthogonally Polarized Compact 8-element MIMO Antenna Using Metallic Stub and Decoupling Unit for Isolation Enhancement of Sub-6 GHz 5G Application

Abstract

A compact dual-feed multiple-input multiple-output (MIMO) antenna is designed for sub-6 GHz 5G applications with isolation enhancement. The proposed dual-polarized MIMO antenna formed by each patch uses two inset-feed lines placed orthogonal to each other with symmetric conditions, which excite each port to resonate at the same frequency (3.65 GHz). The stub is identified diagonally based on plated through-hole technology between orthogonal ports. The structure employs a half mode and maintains minimum interport isolation (≤ −12 dB) of each patch, followed by another patch to form an 8-element miniaturized MIMO antenna. High isolation (≤ −15 dB) is achieved with the help of a decoupling structure placed between the antennas in the ground plane. Measurements of a fabricated prototype validate the simulation results. The diversity performances of MIMO antenna parameters like envelope correlation coefficient (ECC), diversity gain (DG), and Mean Effective Gain (MEG) are also found within acceptable ranges.