A Novel 4× 4 MIMO Antenna Decoupled by T-Shaped Dummy Antenna with High Robustness for 5G Mobile Devices

Abstract

It is challenging to design a compact antenna pair with isolation better than 20 db and with robustness to antenna position. In this paper, a T-shaped dummy antenna is adopted to decouple the tightly arranged antenna pair for 5G mobile devices. Working in the 3.8 GHz of N77 band, the proposed antenna pair is with an impedance bandwidth of 280 MHz. Isolation of the proposed antenna pair is enhanced from 13 db to 30 db by adding the T-shaped dummy antenna, and it is with high robustness even though the antenna position is altered. The calculation process of the loading requirement of T-shaped dummy antenna is shown. By duplicating the proposed antenna pair, a 4×4 MIMO antenna with high isolation is proposed. The measured results show the MIMO antenna with isolation better than 31 db, and the average total efficiency is about 49%, and the Envelope Correlation Coefficient (ECC) is lower than 0.05 in the -6 db pass band. To the best of the authors’ knowledge, compared to most of the reported antenna pairs, the proposed 4××4 MIMO antenna is with the highest isolation while keeping a compact size.