A compact size tri-band MIMO antenna with reduced mutual coupling for WLAN and WiMAX applications

In this paper a tri-band multiple-input-multiple-output (MIMO) antenna is proposed. The MIMO antenna consists of two antenna elements, where each element is designed using rectangular monopole with two asymmetrical L-slots to achieve the required bands operation. The antenna achieved >20dB isolation at all the desired bands (e.g. 2.38-2.74GHz, 3.35-4.02 GHz and 5.18-6.51 GHz), which demonstrate its suitability for WLAN and WiMAX applications. The envelope correlation coefficient (ECC) was found <;0.0015, which suggest independency of antennas' radiation patterns. Furthermore, the antenna exhibits an omni-directional radiation pattern with radiation efficiency of >90%. By using ratio of isolation and size as a new figure-of-merit, the proposed antenna was found to give much higher value as compared experimental results reported in literature. A prototype of the antenna is developed and simulated performances using Keysight Advanced Design System (ADS) are validated against the experimental results.