A 3D-FSS-Based and Front-Feeding Shared-Aperture Base Station Antenna for 5G Mobile Communications

This paper presents a novel compact low-profile dual-polarization base station antenna (or unit cell) designed for 5G mobile communications, which does not require additional baffles. This proposed base station antenna comprises a lower-band (LB) element (2.0-2.6 GHz) and four higher-band (HB) elements (2.7-3.4 GHz). A new three-dimensional frequency selective surface (3D-FSS) is used in the LB element to minimize mutual coupling in this unit cell. Since the operating frequency bands within the HB elements and LB element are adjacent, the coupling between the elements is also a concern. Meanwhile, this paper also proposes a unique front-feeding (Fro-Feeding) and the addition of the extended metal arms(EMA) to hinder the coupling current and achieve effective decoupling. Simulated and measured results show our unit cell reaches a high gain in the LB element (8.3 ±0.5 dBi), with an average increase of 1.1 dBi using front-feeding compared to conventional balun-feeding, and a high gain in HB element (13 ±0.7 dBi). The LB and HB elements exhibit the high port isolation of bigger than 20 dB, the high cross polarization of bigger than 25 dB and stable radiation patterns, fulfilling the requirements for dual-band 5G base station antennas.