H-Shaped Eight-Element Dual-Band MIMO Antenna for Sub-6 GHz 5G Smartphone Applications

Abstract

The design of an eight-element H-shaped dual-band multiple-input multiple-output (MIMO) antenna system for sub-6 GHz fifth-generation (5G) smartphone applications is presented in this work. The radiating elements are designed on the side edge frame of the smartphone, placed on both sides of the main printed circuit board (PCB). Each side edge consists of four radiating elements, which ensures low mutual coupling between antenna elements. The total size of the main PCB is 150×75 mm², while the size of the side edge frame is 150×7 mm². A single antenna consists of an H-shaped radiating element fed using a 50Ω microstrip feeding line designed on the main board of the smartphone. The results show that, according to -6 dB impedance bandwidth criteria, the designed MIMO antenna radiates at two different frequency ranges within the allocated FCC 5G spectrums, i.e., 3.1-3.78 GHz and 5.43-6.21 GHz with 680 MHz and 780 MHz bandwidths, respectively. It is also observed that the antenna elements are able to provide spatial and pattern diversity for both the frequency bands. Furthermore, an isolation of >12 dB is observed between any two given radiating elements. Various MIMO key performance parameters are evaluated, such as channel capacity (CC), envelope correlation coefficient (ECC), and diversity gain (DG). A prototype is fabricated and measured, and it is found that the measured and simulated results are in good agreement. Based on performance attributes, it can be said that the proposed MIMO system may find its application in 5G communication systems.