Compact and High-Performance MIMO Antenna with Metasurface Integration for Millimeter-Wave and Next-Generation 6G Applications

Abstract This study presents a compact four-port MIMO antenna integrated with a metasurface (MS) for high-performance mmWave applications in 5G and future 6G systems. Fabricated on a Rogers Duroid RO3003 substrate, the antenna features a novel circular radiating element and a central feeding mechanism optimized for miniaturization and superior electromagnetic performance. A hybrid design combining a metasurface and a frequency selective surface (FSS) enhances the radiation characteristics. The antenna operates across 24–50 GHz, covering the K, Ka, and Q bands, including the 28 GHz 5G NR band. The MS effectively suppresses mutual coupling between ports through spatial and surface wave suppression, achieving coupling levels better than − 33 dB, while the FSS—comprising two concentric rings and a central disc—enhances gain. These components form a stacked structure with a 5 mm separation. The fabricated prototype shows excellent agreement between simulated and measured results, achieving a peak gain of 10.35 dBi and 90% efficiency. Outstanding MIMO performance is also demonstrated, with a diversity gain of 9.99 and an ECC of 6 × 10 −3 , confirming the antenna’s suitability for advanced wireless and industrial applications.