Experimental Validation of a New Self-isolated Four-port MIMO Antenna System for Heterogeneous Wireless applications

Abstract In this communication, a compact size quad-port MIMO antenna is presented for use in wireless networks including WLAN, Wi-MAX, LTE, UWB and 5G. Significant design challenges for MIMO antenna like size optimization and isolation improvement have been addressed in this study. A four-element self-isolated MIMO antenna is derived from single UWB antenna element. Port-isolation of the antenna is achieved by systematic placement of antenna element on the small size\(\left(25 \mathbf{m}\mathbf{m}\times 25 \mathbf{m}\mathbf{m}\right)\)substrate. The parametric optimization of the antenna is carried out for impedance bandwidth and isolation. The antenna prototype is designed, tested and validated (by comparing simulated and measured results) in this work. In-band reflection \({( \mathbf{S}}_{11}< -10 \mathbf{d}\mathbf{B})\) offered by the proposed antenna is 2 GHz – 30 GHz. Without use of any decoupling structure, the antenna port is isolated by more than − 40 dB. The antenna diversity performance is assessed by the evaluation of Envelope Correlation Coefficient (ECC), Total Active Reflection Coefficient (TARC) and 3D radiation patterns. Comparative study of the proposed antenna is carried out with recent reported literature. The proposed antenna is compact in size, offers larger fractional bandwidth (175%), increased isolation (≤ -40 dB), reduced ECC (0.003), and decreased value of TARC (≤ -20 dB).