Design and testing of a millimeter-wave beam-steering mesh-grid array for 5th generation (5G) mobile communication handset devices

Summary form only given. The steady advancement of silicon and compound semiconductor technologies has triggered the possibility of utilizing millimeter-wave frequencies for next-generation cellular data networks (“5G”). In comparison to 4G networks, the millimeter-wave 5G network offers significant advantage in data throughput due to the much wider RF bandwidth. Recent publications by other authors in (T.S. Rappaport, Y. Qiao, J.I. Tamir, J.N. Murdock, and E. Ben-Dor, Radio and Wireless Symposium, 2012, IEEE, pp. 151-154) have successfully demonstrated the possibility of a millimeter-wave cellular network by characterizing the propagation and angle-of-arrival for an adaptive beam-steering system operating at 38 GHz with full consideration of obstructions by foliage and other structures. However, the advent of an affordable, low-profile beam steering antenna remains one of the most critical issues for future 5G devices. Deployment of a beam-steering antenna array within a cellular handset device is unprecedented in the wireless community. This paper presents a first-of-the-kind phased-array which is specifically conceived for future millimeter-wave 5G cellular networks. The technical challenges associated with the inherent properties of the utilized 28 GHz frequency band and the real-life design constraints in the consumer electronics industry are identified and addressed. The well-understood laser and mechanical via structure within a high-volume printed circuit board technology is used to devise a novel mesh-grid patch antenna element topology. The presented mesh-grid patch features a fan-beam radiation characteristic with a o measured 3dB elevation beamwidth of more than 130 . The required horizontal 2 footprint is less than 3 x 1 mm which is smaller by several factors compared to a conventional Yagi-Uda or a planar dipole topology. Furthermore, the proposed antenna element does not require a ground fill-cut region, greatly alleviating the space - onstraints when integrating within a cellular handset device. The antenna element is further expanded into a beam-steering phased array configuration and integrated within a cellular handset prototype. The far-field radiation patterns of the mesh-grid array are first measured independently in the anechoic chamber and the procedure is subsequently repeated after integration with the 28 GHz RF transceiver unit. The maximum scanning angles for both measurements are controlled by adjusting the phase configurations of each antenna elements within the array. Measurements confirm the 28 GHz mesh-grid array exhibits a o maximum boresight gain of more than 10.5 dBi and ±170 scanning range in the azimuthal plane despite the degradations incurred due to the cellular handset chassis.