A 4-Element MIMO Antenna with Grounded Neutralization Line for 5G Application

A four-element multi-input multi-output (MIMO) antenna with grounded neutralization line for 5G smartphone application is proposed. The MIMO antenna is composed of two pairs of L-shaped monopoles, each pair of which is mirror-symmetrical about the ground for miniaturization. Meanwhile, the size of two L-shaped monopoles is only 10.5×7 mm (0.119 λ 0 × 0.082 λ 0 at 3.5 GHz). Good isolation is achieved by loading the grounded neutralization line between two L-shaped monopoles. Compared with the MIMO antenna without neutralization line, the isolation of the proposed MIMO antenna is improved by 10.5 dB (from 8 to 18.5 dB) at 3.5 GHz.