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 2.4 GHz band (2.4-2.485 GHz) and 5.5 GHz band (5.15- 5.85 GHz). 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 (2.4-2.485 GHz) and better than -26 dB (-30 dB in most of the band) across the higher WLAN band (5.15-5.85 GHz). 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.