Closely located dual PIFAs with T-slot induced high isolation for MIMO terminals

This paper presents an efficient technique to enhance the isolation between two closely spaced PIFAs for MIMO mobile terminals. The proposed decoupling method is based on a T-shape slot impedance transformer and it enables an inter-PIFA spacing of 1 mm to be achieved. The 10 dB impedance bandwidth and 20 dB isolation bandwidth cover the 2.4 GHz WLAN band (2.4-2.48 GHz), with a maximum isolation of 44 dB. The efficiency, gain, radiation patterns of the two-PIFA prototype are also verified in measurements