Tri-band MIMO diversity antenna for modern smartphones

This paper proposes the design of a MIMO antenna system with four elements, specifically tailored for future smartphones. The MIMO antenna system is operating in three important 5G frequency bands: 3.5 GHz, 4.7 GHz, and 5.8 GHz. The MIMO system utilizes a single hybrid H-shaped patch radiator as the radiating element, which is integrated into the smartphone's side-edge frame. The main board of the device consists of the feeding lines. By employing this configuration, the antenna achieves a tri-band response, satisfying the -6 dB impedance bandwidth criteria for each desired frequency band, providing bandwidths of 680 MHz, 440 MHz, and 470 MHz, respectively. The MIMO antenna system also demonstrates notable performance characteristics, including a peak gain of 5.8 dBi, a radiation efficiency of 70%, and a total efficiency of 80%. The strategic placement of antenna elements at the corners of the side-edge frames ensures isolation of greater than 16 dB between the elements in the relevant frequency bands. Furthermore, this antenna design facilitates both spatial and pattern diversity, enhancing the overall performance of the MIMO system.