Investigation of Gap Cavity in Millimeter Multilayer Planar Antenna Array for 5G Applications

The demand for 5G communication systems is to deliver high data rate and to provide larger capacity. Millimeter wave technology is considered to be the best solution for such requirements. 5G antennas are required to have a small size to fit into the commercial cellular handsets, large bandwidth to deliver the required capacity and high gain to combat the high attenuation of mm-waves. In this paper, a reference aperture-coupled four-element multilayer planar array is optimized for operation in the Ka-band. Different gap cavities between the antenna layers are assessed for better performance and ease of fabrication. A low cost millimeter 5G antenna operating at 28 GHz is fabricated and the achieved bandwidth is 7.1% as compared to the 4.6% in the original design.