Low Mutual Coupling Between Mimo Antennas by Using Two Folded Shorting Strips

Abstract—This paper presents a compact dual-band multiple input multiple output (MIMO) antenna with low mutual coupling, operating in the 2.4GHz band (2.4–2.485GHz) and 5.5GHz band (5.15– 5.85GHz). The proposed antenna system consists of two antenna elements located at the top two corners of FR4 substrate (PCB). Each element dimension is reduced substantially by employing a folded structure and slots on the top patch plate, so that it takes up a small volume of 12 × 9 × 6mm3. To enhance port-to-port isolation and efficiency of each antenna, an additional non-radiating folded shorting strip is connected between each antenna element and ground plane of PCB. The measured isolation values are lower than −28 dB over the lower WLAN band (2.4–2.485GHz) and better than−26 dB (−30 dB in most of the band) across the higher WLAN band (5.15–5.85GHz). The improvement in antenna’s efficiency caused to raise up 1 dB of effective diversity gain of MIMO system. Furthermore, S-parameters, radiation patterns and diversity performance characteristics are provided. 1.