Millimeter Wave Dual Polarization Design Using Frequency Selective Surface (FSS) for 5G Base-Station Applications

According to 5G communication bands proposed by various countries, the bands of interest can be divided into 28 GHz/38 GHz and 60 GHz categories, both are millimeter waves. The short wavelengths from the millimeter waves are less likely to propagate (high attenuation), more base stations (i.e., small cells) are required to improve the coverage. Array antennas with beamforming capabilities play another very important role, as a remedy for high attenuation. The antenna proposed in this paper employs a massive dual-polarized MIMO antenna with smart beam switching capability at 38 GHz, in which frequency selective surface was designed to achieve good polarization diversity (decomposition polarization). The frequency selective surface compensates phase delays for electromagnetic waves in space. The phase compensation in our design reached a wider beam angle and had field diversity characteristics. In this article, we first discuss the phase delay of a single FSS and demonstrate the beam diversity using a single antenna with FSS configuration, and finally discuss design improvement using array antenna (that is, replacing the single antenna with an array).