Dual-Band Dipole Antenna with Band Rejection for Base Stations

A proposed multi-frequency dipole antenna with band rejection functionality is mainly composed of a positive and negative 45-degree crossed dipole and a reflector structure. The crossed dipole is fed by two
$50\ \Omega$
coaxial cables to achieve ±45° polarized radiation over a wide bandwidth. The arms of the dipole are elliptical in shape, and they work together with the cross-shaped slot to generate two operating frequency bands. To achieve the band rejection performance of the antenna, the structure has been optimized, and a metal shield is used to ensure stable radiation patterns. Simulation results show that the antenna can radiate at around 3.5 GHz and 4.8 GHz within a frequency range that spans 32% of the center frequency. The band rejection is around 4.1 GHz. The VSWR within the radiation frequency range is less than 2, while the VSWR of the rejected band is greater than 5.5. In the radiation pattern of the antenna, the port isolation of the antenna is less than −20 dB for both ports. The antenna successfully achieved the bandwidth required for 5G base station operation under the conditions of the cross-shaped slot.