Dual-Wideband Dual-Polarized Metasurface Antenna Array for the 5G Millimeter Wave Communications Based on Characteristic Mode Theory

A dual-wideband dual-polarized antenna using metasurface for the fifth generation (5G) millimeter wave (mm-wave) communications is proposed. It is designed and analyzed based on characteristic mode theory (CMT). The proposed metasurface is mainly composed of a $3\times 3$ square-patch, in which its four corner patches are further sub-divided into a $4\times 4$ sub-patch array, while the size of the other four edge patches is reduced and the center patch is etched with a pair of orthogonal slots. By doing so, the side lobe level can be effectively reduced and the main beam radiation can be enhanced. The metasurface is excited by a pair of orthogonally arranged substrate-integrated-waveguide (SIW) to grounded-coplanar-waveguide (GCPW) dual-polarized feeding networks that help to reduce the insertion loss and expand the frequency bandwidth of the feeding ports. In order to yield higher gain, four proposed metasurfaces are fed by a pair of 1-to-8-way power divider feeding networks including a pair of low-transmission-loss E-plane phase shifter. Measured results show desirable impedance bandwidths of 13.85% (24.2-27.8 GHz) and 14.81% (36.9-42.8 GHz) in the lower and upper frequency bands, respectively, and their corresponding average gains are 13.96 and 15.46 dBi.