For future fifth-generation (5G) smartphones, a high-efficiency multiple-input/multiple-output (MIMO) antenna system capable of operating in Long Term Evolution (LTE) 42/43/46 is suggested. A pair of small microstrip-fed slot antenna and inverted F antenna is part of the single antenna design structure. They are positioned on the longer side of the FR-4 printed circuit board. In an effort to lessen the mutual coupling, two antenna elements have a U-shaped rectangular slot inserted between them. The detailed study of the suggested MIMO system includes measurement of the reflection parameter, analyzing the radiation performance, performing envelope correlation coefficient (ECC) and channel capacity calculations, and analyses of the effects of user’s hand in the vicinity of the antenna array. Simulation and measurement results demonstrate the required performance of the proposed design, that is, greater than 80% of total efficiency, isolation >12 dB, and ECC <0.15. The suggested antenna has the benefits of multiband operation, high efficiency, good isolation, and a small footprint.
