MIMO Antenna Module operating in millimeter-wave spectrum, incorporating Pattern Diversity at various angles for 5G IoT applications

Our paper presents a comprehensive study on the simulation of eight antennas tailored for 5G and IoT applications, operating within the 26 GHz band. The research commences with the new structure and analysis of a single-rectangle antenna, integrated into a total ground plane printed on a substrate of ROGERS 5880 with $\varepsilon_{r}=\mathbf{2}.2$ and a thickness measuring $\mathbf{1. 5 7} \mathrm{mm}$. This antenna achieves remarkable performance metrics, covering $S 11_{i}-40 \mathrm{~dB}$ with a gain of 5.2 dBi and an efficiency exceeding $85 \%$. Building upon this foundation, a $2 \times 2$ antenna array is formed with a spacing of 2.8 mm, approximately equivalent to $\lambda / 4$. This arrangement improves the isolation between adjacent antennas by placing them on the back side (or rear side) of the substrate material, while antennas placed diagonally are retained within the same plane. Consequently, isolation levels surpass 20 dB, ensuring minimal interference between antennas. Subsequently, the research progressed to the creation of a $2 \times 4$ MIMO antenna setup by introducing four additional antennas, positioned strategically above and below the $2 \times 2$ MIMO antennas. This extension enhances pattern diversity across both the phi $=0^{\circ}$ and phi $=90^{\circ}$ planes, facilitating robust communication capabilities. The achieved performance metrics underscore the efficacy of the proposed designs in meeting the stringent requirements of 5G and IoT applications in the 26 GHz band.