Design of a Low-Cost Directive Antenna for 5G Small Cells Fronthaul

Optical wireless systems (OWS) has been proposed as promising solution for fronthaul in the small cells of the fifth generation (5G) technology of mobile communication. However, the OWS environmental sensitivity and the need of line-of-sight communication impose the necessity of a backup system to improve reliability. Thus, in this paper, we propose the use of a low cost and high bandwidth microwave system, composed of a highly-directive broadband Yagi-Uda antenna to meet the demands imposed by 5G small cells. The designed antenna was fabricated using an inexpensive FR-4 substrate and operates in a bandwidth ranging from 4 to 5 GHz, exhibiting a VSWR lower than 1.4 and a 12 dBi average gain. Moreover, with the parameters of the designed antenna, we propose a multiband orthogonal frequency division multiplexing (MB-OFDM) system to attend 30 users with a throughput of at least 111.1 Mb/s per user (total of 3.33 Gb/s) over a wireless link of 2 km.