Multi-Mode Smartphone Antenna Array for 5G Massive MIMO Applications

A multi-band antenna array is proposed for 5G massive MIMO systems. The presented antenna not only exhibits multi-band operation but also generates the polarization diversity characteristic which makes it suitable for multi-mode operation. Its configuration contains eight modified planar-inverted F antenna (PIFA) elements located at different corners of the smartphone mainboard. For ease integration and design facilitation, the antenna elements and ground plane are etched on the same layer. For S 11 ≤ -10 dB, PIFA elements of the MIMO design operate at the frequency ranges of 2.5-2.7 GHz, 3.4-3.8 GHz, and 5.6-6 GHz covering the LTE 2600, 42/43, and 47 operation bands. Due to the placement of the antenna elements, the proposed design can support both vertical and horizontal polarizations. Fundamental characteristics of the proposed design are investigated. It offers good S-parameters, acceptable isolation, dual-polarized radiation coverage, and sufficient efficiency. In addition, the calculated TARC and ECC results of modified PIFAs are low over the operation bands.