This paper presents an eight-element dual-band MIMO antenna array designed for seamless integration into contemporary smartphones, addressing the growing demands of 5G communication within the sub-6 GHz spectrum. The antenna operates across two critical frequency bands: 3.37-3.61 GHz and 4.9-5.1 GHz, achieving impressive efficiency and performance metrics. Each antenna element measures 20 × 11.8 mm², and a strategic decoupling structure (Section Dx) is included to enhance isolation among radiating elements, achieving isolation levels exceeding -14 dB and an Envelope Correlation Coefficient (ECC) below 0.05 in the lower frequency band and 0.02 in the higher band. The antenna array exhibits an efficiency ranging from 48.5% to 63.7%, a channel capacity of 38.8 bps/Hz, and a gain of 3.9 dBi, making it suitable for integration into smartphone devices and advancing the next generation of mobile communication technologies. The design is optimized for simplicity in manufacturing and MIMO characteristics, avoiding the complexity of external decoupling structures. The paper also includes detailed results and discussions on antenna evolution, scattering parameters, parametric analysis, radiation patterns, MIMO diversity parameters, and hand analysis, demonstrating the antenna's robust performance and compliance with safety standards.This paper presents an eight-element dual-band MIMO antenna array designed for seamless integration into contemporary smartphones, addressing the growing demands of 5G communication within the sub-6 GHz spectrum. The antenna operates across two critical frequency bands: 3.37-3.61 GHz and 4.9-5.1 GHz, achieving impressive efficiency and performance metrics. Each antenna element measures 20 × 11.8 mm², and a strategic decoupling structure (Section Dx) is included to enhance isolation among radiating elements, achieving isolation levels exceeding -14 dB and an Envelope Correlation Coefficient (ECC) below 0.05 in the lower frequency band and 0.02 in the higher band. The antenna array exhibits an efficiency ranging from 48.5% to 63.7%, a channel capacity of 38.8 bps/Hz, and a gain of 3.9 dBi, making it suitable for integration into smartphone devices and advancing the next generation of mobile communication technologies. The design is optimized for simplicity in manufacturing and MIMO characteristics, avoiding the complexity of external decoupling structures. The paper also includes detailed results and discussions on antenna evolution, scattering parameters, parametric analysis, radiation patterns, MIMO diversity parameters, and hand analysis, demonstrating the antenna's robust performance and compliance with safety standards.