Broadband Dual-Polarized Base Station Antenna for LTE/5G C-band Applications

In this paper, a broadband ±45°dual-polarized base station antenna excited by a square loop structure is proposed. The operating bands of the proposed design are in LTE2300/LTE2500/C-Band/5G (3300-3600MHz). The antenna consists of two pairs of coplanar symmetrical dipoles, and two microstrip lines, and square loop-shape structures, and two metal cylinders and a reflector. The square loop-shape structure connected by the microstrip line is electromagnetically coupled to feed the dipoles, and its dipoles and metal cylinder are connected to the reflector. By changing the geometry of the square loop structures and symmetrical dipoles, the impedance bandwidth of the design is 55.88% (2.05 - 3.64 GHz), when the impedance bandwidth and isolation are defined by S11 less than -10dB and S21 less than -20dB separately. The simulated half-power beamwidth (HPBW) of the design is greater than 60 degree at 2.3 GHz, 3 GHz, and 3.6 GHz, and the simulated gain is from 5.01dBi to 8.58dBi. Since port1 and port2 are almost symmetrical, there is a stable radiation pattern in both +45°-plane and -45°-plane. In addition, the overall antenna architecture is simple and easy to fabricate in base stations that can be used in 4G and 5G mobile communication systems.