Numerical Analysis of Users’ Body Effects on a Fourteen-Element Dual-Band 5G MIMO Mobile Terminal Antenna
This paper studies the performance of a 14-element dual-band 5G MIMO antenna with body effect and an antenna selection. The antenna operates in the lower frequency band from 3.10 to 3.85 GHz for 5G bands of LTE 42 and 43, whereas the upper band is from 5.60 to 7.20 GHz for the newly assigned 6 GHz WiFi band. The antenna performance was evaluated in free space and under the effect of human body in three scenarios, namely one-hand, two-hands, and call mode. All resulting envelope correlation coefficients are less than 0.3. On the other hand, the free space efficiency of the antenna elements is between 41 % to 77 % in the lower band and 61 % to 95 % in the upper band. Meanwhile, the efficiency of the elements varies depending on the interaction between each element with the hands and the head, with the least obstructed element efficiency degrading to 8 % relative to free space levels. Due to the body effect, multiplexing efficiency loss varies from 2.68 dB to 5.93 dB and the capacity loss is from 14 % to 38 %. Finally, a selection algorithm is used to assess the performance of the overall antenna when 12, 10 and 8 antenna elements are selected for operation. In free space and with number of elements 12, 10 and 8, the system achieves 91.7 %, 80 % and 67 % from the capacity of the 14-element MIMO antenna, respectively. However, in the vicinity of the body, these values increase to 96.3 %, 85.0 % and 72 % from the capacity of the 14-element MIMO antenna, respectively. This signifies that the less-contributing elements as a result of body blockage can be deselected in order to preserve system resources that these elements consume while contributing less significantly to the performance.