Dual-band 8-element MIMO antenna with short neutral line for 5G mobile handset

A design of compact dual band 8-element MIMO antenna using folded monopole structures is proposed. The MIMO antenna consists of 8 folded monopole antenna elements, each two of them are symmetrically placed on the orthogonal frame corners of the substrate, and closely located to each other with no clearance on the ground. The folded monopole arms are used as radiation elements to resonate at two different bands of 3.4-3.6 GHz and 4.55-4.75 GHz. Each closely placed two antenna elements are connected by a 3 mm short neutral line which can be used to reduce the mutual coupling at both bands. By optimizing the antenna structure and neutral line, dual band decoupling can be achieved. The isolation and efficiency of the MIMO antenna is improved and the calculated ergodic channel capacities with a 20 dB SNR at both bands reach to 41.2 bps/Hz and 40.3 bps/Hz, respectively, very close to the ideal case of 8×8 MIMO system.