Beam-Steerable Antenna Array with Metasurface at Millimeter Wave Frequency Range

This work demonstrates a beam-steering antenna operating at 28 GHz, thus supporting millimeter wave (mm-wave) 5G applications. The proposed antenna configuration is composed of a bi-layered structure. The bottom layer consists of antenna elements with 2x2 Butler matrix (BM) based feed network used to excite the antennas as well as to steer the beam at different angles by introducing the phase difference between the two antenna elements. The bottom layer is modeled on Rogers RT5880 substrate with 0.254 mm thickness. The top layer is composed of metasurface consisting of a 4 x 4 square-ring element array designed on the Rogers RT5880 substrate with 0.508 mm thickness. The use of the metasurface in this work is to further enhance the scan angle of the proposed antenna. The presented antenna system acquires an operating bandwidth of 3.4 GHz ranging from 26.7-30.1 GHz. In addition, gain of 11.8 dBi and 7.8 dBi is demonstrated at 28 GHz for the butler matrix antenna without and with metasurface, respectively. The 2D radiation patterns exhibit beam steered at angles of +/- 35 degrees at the desired frequency. The analysis of the obtained results affirm the proposed beam steerable antenna array as a suitable contender for mm-wave 5G devices.