Abstract
This paper presents a high-performance four-element button mushroom MIMO antenna tailored for sub-6 GHz fifthgeneration (5G) wireless communication systems. The antenna is fabricated on an FR4 epoxy substrate with a dielectric constant of 4.4 and a thickness of 1.6 mm, offering a cost-effective and mechanically robust solution. The design comprises rectangular patch elements optimized for dual-band operation at 3.48 GHz and 4.75 GHz, effectively covering key segments of the sub-6 GHz 5G spectrums. A button mushroom structure is incorporated between elements to significantly reduce mutual coupling and enhance isolation, achieving values consistently below –20 dB across the targeted bands. Simulations conducted using Ansys HFSS demonstrated excellent MIMO performance, with an envelope correlation coefficient (ECC) of less than 0.03, channel capacity loss (CCL) below 0.4 bits/s/Hz, and diversity gain (DG) approaching 10 dB. The antenna supports a total bandwidth of 2.11 GHz, ensuring reliable wideband performance. Experimental validation using a vector network analyzer and anechoic chamber confirmed the simulation outcomes. The compact size, high isolation, and wide operational bandwidth make the proposed antenna a strong candidate for modern 5G MIMO applications. Future enhancements may include the integration of tunable components for dynamic frequency adaptability and Specific Absorption Rate (SAR) analysis for user safety and regulatory compliance.
Keywords: C-band, Multiple Input Multiple Outputs, n77, n78, 5G Application.