Dual-port EMNZ Massive-array Metamaterial as a Self-radiating Multiband MIMO Aperture for Sub-6 GHz Systems

This work presents a self-radiating dual-port electromagnetic near zero (EMNZ) metamaterial, acting as a small two-element multiple-input multiple-output (MIMO) aperture without the use of typical antenna elements.The proposed design comprises a Split Ring-slot (SRS) unit cell array arranged in 10 by 10 configuration printed on a single layer FR-4 substrate and excited directly using two SMA ports with microstrip feed networks located on opposite edges of the structure.Each port initiates a different guided surface mode that couples to the EMNZ medium and radiates using controlled leaky wave behavior where it itself becomes the radiating element.Full-wave simulations and experimental measurements prove the existence of four strongly defined resonant bands with frequencies of 5.18, 5.48, 6.17, and 7.23 GHz with deep return-loss minima of -46.89 dB.The two port configuration has good intrinsic MIMO characteristics, such as envelope correlation coefficient (ECC) is about 0.02, diversity gain is about 10 dB and isolation level is more than 40 dB across the resonant bands The reduced spatial correlation enables an improved eigenvalue distribution of the effective MIMO channel, resulting in approximately 15-18% enhancement in ergodic channel capacity compared to a correlated dual-port reference.Electromagnetic safety evaluations also provide additional assurance of full FCC and ICNIRP SAR and power density compliance.The proposed dual-port EMNZ metamaterial is a low-cost, scalable and compact radiating solution for multiband sub-6 GHz MIMO platforms, which serves as an alternative to conventional antenna array for 5G, Wi-Fi 6E, IoT gateways and massive-MIMO communication systems.