Compact frequency reconfigurable MIMO antenna pair with high isolation for 5G mobile applications

Abstract

This article presents a design of compact frequency reconfigurable dual-port antenna pair with high isolation for 5G mobile devices. Two feeding ports are located side by side and share a common radiator within a small area of 11.5 mm  6 mm in the proposed antenna pair. The feeding ports achieve a self-decoupling characteristic without any additional decoupling structure based on a synthesis of common and differential modes in the shared radiator.Moreover, the antenna pair has a frequency reconfigurable property and can operate in both 3.5 GHz and 5 GHz bands by switching PIN diodes. A prototype multiple-input-multiple-output (MIMO) antenna composed of four designed antenna pair is fabricated and tested. The experimental results show that the antenna pair can operate in both the frequency bands and has peak isolations of 26 dB in 3.5 GHz band and 27 dB in 5 GHz band. The antenna efficiencies are around 60% at 3.5 GHz and about 80% at 5 GHz respectively. The proposed antenna pair can be a promising candidate for 5G applications.