4-Port High-Gain Metamaterial-Inspired Element-Based MIMO Antenna Array for 5G mmWave Applications

Millimeter-wave 5G devices need compact MIMO arrays that provide high gain while minimizing inter-port coupling; conventional arrays struggle to balance gain, bandwidth, and isolation in small footprints.This article discusses a compact, high-performance four-port orthogonal MIMO antenna system for millimeter-wave 5G uses that works in bands n257(26.50–29.50 GHz), n258(24.25–27.50 GHz), and n261(27.50–28.35 GHz). Each of the four ports has a 4x4 sub-array with a total of 16 elements (individual element small size with dimensions of 0.32λ0×0.26λ0 excluding feed), along with a 13x10 double-negative (DNG) metamaterial reflector. The antenna is built on a Rogers 5880 substrate, which is well-known for having great dielectric characteristics. The antenna has dimensions of 4.86λ0 × 4.81λ0 × 0.073λ0, but it has a high gain of 14.3 dBi, a wide spread of 8.06 GHz, and a 97% radiation efficiency. Adding metamaterials that have negative permittivity, permeability, and refractive index greatly improves performance by getting excellent isolation of more than -32.7 dB and increasing the bandwidth by 200 MHz. The metamaterial’s unit cell was modeled with CST and validated by showing an identical circuit in ADS. A prototype antenna design was Fabricated and measured and the results were closely matched the simulations. Five machine-learning regression models were also used to verify and evaluate the antenna’s performance, including its gain. Support Vector Regression (SVR) and Extreme Gradient Boosting (XGB) methods were the most accurate, with 96% or more prediction accuracy. The results show that the suggested MIMO antenna system based on metamaterials works well and can be used in real-life 5G scenarios.