Design, Simulation, and Optimization of a Port MIMO mmWave Microstrip 4x5 Parallel Array Antenna

Abstract

Millimeter-wave (mmWave) multiple-input multiple-output (MIMO) antenna technology is a critical enabler of next-generation wireless communication systems, offering high data rates, improved spectral efficiency, and robust connectivity. This paper presents the design, simulation, and optimization of a 4-port MIMO mmWave microstrip 4×5 parallel array antenna operating across the 84–98 GHz frequency range. The proposed antenna is developed through four systematic stages: (1) designing a mmWave unit-cell 1×5 serial array antenna, (2) designing a mmWave T-junction 1×4 power divider, (3) developing a mmWave microstrip 4×5 parallel array antenna, and (4) implementing the four-port MIMO configuration. The antenna is fabricated on an Isola Astra MT-77 low-loss substrate, and all simulations are performed using the Finite Integration Technique (FIT) electromagnetic solver within CST Microwave Studio (CST MWS). Performance evaluation demonstrates that the proposed antenna achieves a broad impedance bandwidth of 18.44 GHz (80–98 GHz), a peak realized gain of 16.4 dBi, high directivity, and strong port isolation, with envelope correlation coefficient (ECC) values below 1.1×10⁻⁵,, confirming excellent MIMO diversity performance. The obtained results demonstrate that the proposed design outperforms several existing state-of-the-art mmWave MIMO antenna designs reported in the literature, making it a strong candidate for 5G and beyond wireless communication applications.