Design of the MIMO Antenna for Mobile Communication Terminal

The MIMO antenna for mobile communication terminals is proposed for improving its communication ability in different networks. It can avoid the problem of signal attenuation and poor signal quality caused by antenna band mismatch. The dimension of the overall antenna size is 58mm×120mm (0.68λ
0
×1.41λ
0
, where λ
0
is the wavelength of 3.5GHz). The MIMO antenna can cover the following areas: GSM 1800, UMTS, LTE, and 5G band N78. The proposed antenna consists of two types of radiating units, including an E-type radiating unit and an L-type radiating unit. The E-type radiating unit contains two frequency bands of 1.71 ∼ 1.75GHz and 3.36 ∼ 3.61GHz respectively, which is worked for GSM1800 and 5G band N78. The L-type radiating unit covers 2.58 ∼ 2.69GHz, after moving the L-type patch, it can cover 2.05 ∼ 2.17GHz, which works for UMTS and 5G band LTE. The E-type patch antenna is center symmetric loaded to improve the gain of the proposed MIMO antenna. The simulation results show that the antenna’s efficiency is higher than 80% in 2.1GHz, 2.6GHz, and 3.5GHz bands with ECC (Envelope Correlation Coefficient) less than 0.16. A prototype of the proposed 6-antenna array is manufactured and measured. The measurement results show a return loss of 8.72dB and an isolation of 14.83dB, basically consistent with simulation results. It is also worth noticing that the proposed antenna could operate in the highly anticipated next-generation Wi-Fi 6E.