The optimization of multi-port massive MIMO antennas requires careful design development for future IoT applications, which will require large-scale connectivity. This paper presents a simulation and measurement of a twenty-element MIMO antenna system suitable for the golden band (7.1−8.4 GHz), which can be implemented in current smartphones according to the World Radiocommunication Conference 2023 (WRC-23). The proposed system has dimensions of 158 mm \(\times \) 60 mm with 24.52% bandwidth while incorporating the planar dielectric material FR-4, which leads to a design–cost trade-off. Multiple unit antenna development requires maintaining spatial attributes alongside lowering element-to-element mutual coupling that results from partial and connected ground planes for achieving isolation of \(-17~\hbox {dB}\) and the 0.05 of ECC. Each antenna maintains high performance because of its precise positioning elements and accurate geometric transformations, which are proven by the evaluation of reflection coefficients together with radiation patterns and the gain with 5.2 dBi. Moreover, the optimum bandwidth efficiency and the ability to reduce channel capacity loss and achieve better diversity gain by implementing a twenty-element MIMO system fulfill the criteria of current wireless communication standards to support future smartphone applications with higher data rates and dependability. The choice of FR-4 substrate can be used to address key concerns of better performance at lower costs while also being commercially viable and helping broadly advance the state-of-the-art smartphone antennas for higher data rates.
