A Compact Boat Shaped Dual-Band MIMO Antenna With Enhanced Isolation for 5G/WLAN Application

This work envisioned presenting a novel compact boat-shaped dual-band Multiple Input- Multiple Output (MIMO) antenna for isolation enhancement of 5G/WLAN application. Each identical rectangular patch consists of stubs, a defective ground structure and a split ring resonator placed on a defective ground plane to generate 2.32 GHz and 5.2 GHz for dual-band operation and make a low profile. The MIMO antenna design is challenging due to size constraints and mutual coupling. The 2-port MIMO antenna is realized using the diagonal deployment of symmetric radiators on an FR-4 substrate, consuming an entire size of $2103.93\,\,mm<^>{2}\times 1.6$ mm. The impedance bandwidth is enhanced by incorporating a shorting pin, covering 2.22 to 2.42 GHz (200 MHz) and 5.142 to 5.706 GHz (564 MHz). Meanwhile, to overcome the mutual coupling effects and improve isolation, an innovative hybrid decoupling structure (ladder-shaped slot and neutralization line) is introduced between the bottom and top of radiating elements. It suppresses the surface waves with maximum isolation better than -46 dB & -45 dB at 2.32 GHz and 5.2 GHz, respectively. Furthermore, the MIMO performance metrics, such as envelope correlation coefficient (< 0.001 dB) and diversity gain (>9.99 dB), are analyzed. The diversity performance results demonstrate that the MIMO antenna is apt for 5G / WLAN terminal devices.