The efficacy of including a defected ground structure (DGS) for mobile communication on a mobile phone PCB in improving the multiple input multiple output (MIMO) system performance is evaluated and demonstrated in the context of single and multiple-element two-port planar inverted-F antennas (PIFAs). The proposed scheme designed and developed for operation in the 3.5 GHz long term evolution (LTE) and future 5G frequency bands demonstrates efficiency improvement by 15% and capacity improvement by around 7% because of the significant reduction in mutual coupling between the antenna ports. Results in free space as well as next to a human head and hand phantom are presented.
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