A Planar MIMO antenna for 5G n77/78/79 and 5G WiFi Applications

This paper proposes the design of a planar dual-frequency monopole MIMO (Multiple-Input, Multiple-Output) antenna. The proposed structure consists of a C-shaped feeding monopole, an F-shaped strip, an L-shaped strip, a rectangular branch, and a modified ground plane. On a finite common ground plane, surface currents tend to cause strong mutual coupling between the two antenna elements. To address this, a Y-shaped neutral line is added between the two elements to achieve high port isolation. Two identical antenna elements are arranged orthogonally, which can achieve polarization diversity and further enhance port isolation. The presented MIMO antenna is printed on a size of 45 × 45 × 1.59 mm3 FR4 substrate. The −10 dB reflection coefficient bandwidth is 460 MHz (3.37–3.83 GHz) and 1060 MHz (4.79–5.85 GHz) in the lower and higher frequency bands, respectively. The isolation is larger than 15 dB in both operating frequency bands. The efficiency is more than 47%, and the envelop correlation coefficient (ECC) is below 0.02. The antenna has bidirectional radiation characteristics and reasonable gain in the lower and higher frequency bands. The antenna is desirable for 5G n77/78/79 and 5G WiFi wireless communication systems.