This study introduces a miniaturized two-port antenna array designed to support sub-6 GHz in-band full-duplex and MIMO systems with high isolation requirements. To achieve a compact footprint without sacrificing performance, the design integrates two closely spaced radiating elements that utilize an optimized isolation structure to ensure strong port decoupling. Simulation data indicates robust performance at 4.3 GHz, with inter-port isolation maintained above 30 dB throughout the target frequency band. Furthermore, the antenna demonstrates stable radiation patterns and a low Envelope Correlation Coefficient (ECC), ensuring effective diversity gain. Despite its reduced physical dimensions, the proposed design yields satisfactory gain, making it a viable candidate for modern wireless applications operating below 6 GHz.