ABSTRACT A novel low‐profile dual‐band 8‐antenna multiple‐input multiple‐output (MIMO) array is presented for the fifth‐generation (5G) smartphone antenna design. The proposed 8‐antenna array consists of four pairs of monopole antennas that are vertically printed along with the two long side‐edge frames of the 5G smartphone, while each pair of monopole antennas is composed of two symmetrical bending monopoles linked via a meandering neutralization line (NL), which can effectively reduce the overall antenna size. Here, each bending monopole (array element) can effectively excite the desired dual‐band (3.3–3.6 GHz and 4.8–5.0 GHz) operations planned by the Ministry of Industry and Information Technology (MIIT) of China. Notably, even though the two adjacent bending monopoles have a low profile of only 5 mm (0.058λ 0 @ 3.5 GHz) and the separation gap distance between them is very narrow at 3 mm (0.035λ 0 @ 3.5 GHz), good isolation (> 10 dB) can still be achieved across the two bands of interest due to the NL. Furthermore, the envelope correlation coefficient (ECC) between any two array elements is below 0.1, indicating good independence in far‐field radiation characteristics.
Huang et al. (Wed,) studied this question.