An ultra-wideband MIMO antenna for 5G smartphone

In this letter, a multiple-input and multiple-output (MIMO) antenna with ultra-wideband performance for 5G smartphones is investigated. Firstly, a compact antenna-element with a size of 8 x 7 mm2 is proposed. The antenna-element is designed as a shorted rectangular patch with a reclined-F slot etched on it. The antenna element operates with a wide bandwidth of 88% which is contributed by the multiple-mode resonance and L-shaped coupling excitation. Then, eight identical antenna-elements are arranged on the bezels to constitute an 8 x 8 MIMO antenna. At last, to demonstrate our design mechanism, a prototype of the proposed MIMO antenna is fabricated and measured, achieving a good agreement between the measurement and simulation. The proposed MIMO antenna covers the entire 5G NR bands and part of the LTE bands with decent in-band isolations higher than 10 dB and total efficiencies varied from 40% to 75%.