A Compact Four-port High Isolation ACS Fed Dual Band MIMO Antenna with L-shaped Branches for Wireless Applications

A compact ACS fed 4-port Multi-Input-Multi-Output (MIMO) antenna with dual-band characteristics is presented in this work. The presented MIMO antenna with dimensions of $37 \times 37 \times 1.6 {\mathrm {mm}}^{3}$ is etched on the highly available substrate (FR-4) having $\varepsilon r = 4.4$ and $(\tan \delta) = 0.02$. The required isolation ($S_{21}-17$dB) for the presented MIMO is accomplished by placing the antenna elements orthogonal manner. This MIMO antenna is designed to operate in dual bands with good return loss characteristics $(S_{11} \lt -10$dB). The lower band ranges from 3–3.6GHz which covers the WiMAX band while the upper band ranging from 4.2–6GHz, covers the 3.5/5.5GHz WiMAX and 5.2/5.8GHz WLAN bands. The presented MIMO system exhibits a maximum average peak gain of 4dB and efficiency of 82–85%. Various diversity parameters such as ECC, DG, MEG, TARC, and CCL are investigated to examine the MIMO system performance and are within acceptable limits.