Microstrip MIMO Antennas for High-Band in 5G Systems

This article presents the design and analysis of microstrip MIMO antennas intended for operation in the 5G high-frequency band (High-Band). The proposed antenna structures include 2 and 4 element MIMO configurations operating in the millimeter-wave spec-trum with a center frequency of 38 GHz. The aim of the article was to develop compact antenna systems with performance parameters suitable for 5G mmWave applications, while addressing the limitations of microstrip technology. This article describes the development process of a single radiating element and its subsequent integration into multi-antenna structures. Particular attention is paid to impedance matching, port isolation, and mutual coupling mitigation, which represent key challenges in implementing MIMO antennas within the millimeter-wave band. Furthermore, the impact of the number of antenna elements on the radiation pattern, gain, and overall efficiency of the MIMO system is analyzed. The obtained results confirm that MIMO microstrip antennas in 2- and 4-element con-figurations can be an effective solution for 5G High-Band applications, providing ade-quate radio parameters while maintaining small dimensions and the ability to integrate with RF front-end systems. The presented solutions can be used in user terminals, CPE modules, and compact access stations of 5G systems operating in the millimeter-wave band.