A Dual-Band Dual-Polarized Base Station Antenna Using a Novel Feeding Structure for 5G Communications

A dual-band dual-polarized base station antenna for the fifth-generation (5G) mobile system is presented in this paper. The proposed antenna covers the frequency bands from 3.3 to 3.8 GHz (the lower band) and from 4.8 to 5.0 GHz (the upper band) with good isolation between its ports (>= 20 dB). It consists of two double-oval-shaped dipoles, two double-oval-shaped feeding lines and a cavity reflector. In this design, parts of the dipole antenna structure are used as the feeding lines and it is found that using one arm of the dipole to feed the whole antenna can improve impedance matching. The dual-band performance is achieved by integrating a small oval-shaped loop within the large oval-shaped loop without increasing the size of the radiating patch. The size of the radiating patch is only 0.26 lambda(0) x 0.26 lambda(0) (lambda(0) is the free-space wavelength at 3.3 GHz). The cavity reflector improves the gain performance and reduces the overall size of the antenna, which is only 0.66 lambda(0) x 0.66 lambda(0) x 0.2 lambda(0). The antenna has an average realized gain of 7.56 dBi in the lower band and 7.42 dBi in the higher band. Meanwhile, for both bands, the radiation pattern is stable, and the half power beamwidth is within 65 degrees +/- 5 degrees. Both simulated and measured results demonstrate that the antenna is a very good candidate for 5G mobile base stations.