3.6‐GHz 10‐antenna array for mimo operation in the smartphone

A 10‐antenna array operating in the 3.6‐GHz band (3400–3800 MHz) for multi‐input multi‐output (MIMO) operation in the smartphone is presented. Each antenna in the proposed array is a microstripline‐fed open‐slot antenna with same small dimensions of 3 × 8 mm 2 (0.036λ × 0.096λ, λ is the wavelength at 3.6 GHz). The proposed array consists of two symmetric five‐antenna arrays disposed, respectively, along two long side edges of the system ground plane of the smartphone. The proposed array is expected to be placed in the narrow spacing between the display panel and the long side edges of the smartphone. Acceptable isolation (better than about 10 dB) and good envelop correlation coefficient (ECC) of less than 0.1 for any two antennas in the proposed array is obtained. The maximum channel capacity of the proposed array in a 10 × 10 MIMO system is calculated to reach about 47 bps/Hz at 20‐dB signal‐to‐noise ratio, which is larger than four times that (11.5 bps/Hz) of the upper limit of an ideal 2 × 2 MIMO system with 100% antenna efficiency and zero ECC between antennas. Details of the proposed 10‐antenna array are described, and the experimental results are presented and discussed.