LAUSR

In this article, a compact, wideband Yagi-Uda antenna and its phased array antenna is optimized by a multi-objective antenna for the millimeter-wave (mmWave) band of fifth generation (5G) communication systems. Ten geometrical parameters of a single Yagi-Uda antenna are selected to widen the 5G operating bandwidth (BW) and increase the gain together using the Kriging model builder and pipeline sequential design (PLSD) in combined sampling strategy. The single antenna element provides a wide impedance bandwidth (IBW) from 26 to 34 GHz with 20% and a peak measured gain of 5.5 dBi at frequency 28 GHz. The optimized antenna provides a high growth of 27.7% and a 2 dB increase in peak gain over the reference antenna without any effect on the structure design. Then, a low-bit phased array antenna with the optimized 5G Yagi-Uda antenna is designed and optimized with directional radiation in the horizontal plane for the 28 GHz base-station (BS) 5G applications. The array antenna consists of three sections: the Yagi-Uda antenna elements, Wilkinson power divider, and two bits phase shifters. The total size of the proposed array antenna is $60 \times 47\ \text{mm}^{2}$ and it operates in a measured frequency range of 26.2 to 29.1 GHz around an operating frequency of 28 GHz which provides 10.3% IBW, and a maximum measured gain is 14 dB. Finally, two analog and hybrid precoding methods are considered to evaluate the performance of the proposed 5G phased array antenna. In the analog precoding, gain patterns are nearly constant in the range of $[-45^{\circ }, 45^{\circ }]$ with variations around 1 dB and the range for hybrid precoding, is $[-60^{\circ }, 60^{\circ }]$ with a very low sidelobe level (SLL). Measurement and simulation results complied well. Finally, a dual beamforming scheme is tested for mmWave (5G) vehicle-to-vehicle (V2V) communication systems in several channel models by an experimental test that shows the compatibility of this array antenna in mmWave V2V communications.