Design of Low Mutual Coupling MIMO Antenna for 2.4 GHz Using Orthogonal Polarization Diversity

Abstract

This paper presents the design and simulation of a compact multiple-input multiple-output (MIMO) antenna structure optimized for operation within the 2.4 GHz frequency band, which is widely utilized in wireless applications such as Wi-Fi, Bluetooth, and various Internet of Things (IoT) devices. The proposed MIMO antenna features a novel configuration, incorporating a modified rectangular patch on a cost-effective FR-4 substrate. To improve isolation between the two antenna elements within the operating band, orthogonal polarization is employed, effectively minimizing mutual coupling and enhancing overall MIMO performance. Simulation results demonstrate excellent impedance matching at the target frequency, with a return loss S₁₁ of –26 dB around 2.4 GHz, indicating minimal reflection and efficient power transfer. The antenna exhibits stable performance across the 2–3 GHz range, with a distinct resonance peak confirming its narrowband characteristics. The envelope correlation coefficient (ECC) is very close to zero, indicating low signal correlation between the elements and resulting in high diversity gain (DG) at the operating frequency. These results highlight the suitability of the proposed MIMO antenna for integration into modern embedded and portable wireless communication systems.