# Design of Massive MIMO Antenna System for 5G Base Stations

Design of Massive MIMO Antenna System for 5G Base Stations. Masters thesis, King Fahd University of Petroleum and Minerals.

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In this work, we provide a novel solution for future base station antenna systems. Future base station antenna systems will have powerful capabilities such as providing multiple simultaneous beams to large number of users to enhance the link quality and increase data throughput. The concept of massive multiple-input-multiple-output (mMIMO) weill be implemented. The presented design is the first to provide two modes of operation; namely multiple individual ports mode and beam switching mode for future 5G base station systems.\\ A 72 port mMIMO antenna system with switch beamsteering capability is presented for 5G base stations. Each side of the triangular antenna system consists of 3 layers with a total size of 44.4$\times$29.6$\times$0.1524 cm$^3$, and contains 24 ports. Each port (subarray) consists of 2$\times$2 patches on the top layer, feeding lines with pre-calculated phases on the bottom layer and the ground layer is the middle one. The operating frequency is the potential 5G 3.6 GHz band. Each subarray (one port) is fed in a way to tilt its beam direction with respect to others to achieve uncorrelated channels. The design is fabricated and measured to test its performance. The minimum measured bandwidth is 100 MHz. The gain of a single port equals to 9.4 dBi. The envelop correlation coefficient does not exceed 0.12.\\ The array operates in two modes; large MIMO and Beamsteered mMIMO. An algorithm to steer the beam of each 24-port side to different directions in space is derived and applied. 12 switched beams are obtained with elevation coverage up to 30 $^o$. The total gain of the array dropped from 18.9 dBi at broadside direction to 11.93 dBi at 30 $^o$ in elevation. The sidelobes also dropped from 11.2 dBi to 4.53 dBi. The half-power beamwidth (HPBW) is about $9\ ^o$ at broadside, and it is 20 $^o$ in elevation direction and 26 $^o$ for the azimuth one in the direction of 30 $^o$ beam.