Bancha Luadang, Pisit Janpangngern, Khanet Pookkapund, Sitthichai Dentri, Monai Krairiksh, Chuwong Phongcharoenpanich
This research proposes a broadband unidirectional twin-element multiple-input-multiple-output (MIMO) antenna scheme for mid-band 5G and WLAN applications. The twin-element antenna scheme comprises two single-element antennas, and each single-element antenna consists of a T-shaped hemispherical feeding patch, left- and right-arm radiating patches, and a conjoined triangular ground plane. The twin-element MIMO antenna scheme is integrated with a laptop model functioning as the reflector. The measured impedance bandwidth (|S|, |S|������-���6 dB) are 55.32%, covering 3.4-6.0 GHz, and the measured mutual coupling (|S|) is less than -���15 dB. The measured gain at the center frequency (4.5 GHz) is 4.585 dBi. Besides, the measured xz- and yz-plane cross-polarization levels are below -���25 dB and -���15 dB, respectively. The half-power beamwidth (HPBW) in the xz-plane at 3.5, 4.5, and 5.5 GHz are 99��, 92.8��, and 84.2��, and the corresponding HPBW in the yz-plane are 102��, 78��, and 102��. The measured xz- and yz-plane back lobe levels are below -���15 dB across the entire operating frequency band (3.5-5.5 GHz). The radiation pattern of the twin-element MIMO antenna scheme is of unidirectionality. Furthermore, the envelope correlation coefficient and diversity gain of the twin-element antenna scheme are���<���0.001 and���>���9.99 dB, respectively. The proposed broadband unidirectional twin-element MIMO antenna scheme is thus operationally suitable for mid-band 5G/WLAN communication systems. Essentially, this research is the first to propose a broadband twin-element MIMO antenna scheme for mid-band 5G/WLAN applications.
