High Gain Horizontally Polarized Omnidirectional Slot Antenna Array for Base Stations

A compact horizontally polarized omnidirectional (HPO) slot antenna array is presented for base stations. It is made up of four antenna units, each of which obtains HPO radiation pattern by etching vertical slots on the four faces of the metal shell. The simulation results demonstrate that the gain variations of this antenna unit are not more than 2.5 dB in the azimuthal plane over the frequency band 2.38-2.51 GHz, which covers the frequency range of wireless local area network (WLAN) system. Besides, the peak gain is around 2.8 dBi and the cross-polarization (X-pol) level is less than -30 dB in the entire band. Then, a four-unit antenna array is designed to meet the high gain requirements of the base stations. Simulations show that the presented antenna array has a bandwidth of 3.68% (2.40-2.49 GHz) and a peak gain approximately 8.6 dBi. Besides, the gain variations are not more than 3.5 dB for the horizontal radiation pattern.