Design of broadband dual-polarized oval-shaped base station antennas for mobile systems

This paper proposes a new design of wideband oval-shaped antenna with ±4° dipoles suitable for the base station of mobile communication systems. The designed antennas cover bands of 700-960 MHz (the lower band antenna) and 1700-2700 MHz (the upper band antenna) for cellular 2G/3G/LTE technologies. The design enjoys the advantages of stable directivity and beamwidth within frequency bands and a simple feeding structure with a compact size and low profile. The oval-shaped structure makes the antenna smaller in size than other polygon shapes. The antenna in the lower band has a beamwidth of 85.4°± 1.3° and directivity of 7.2±0.13 dBi with the reflection coefficient ≤ -17 dB and the isolation between the ports ≥ 19 dB while the antenna in the upper band has a beamwidth of 84.15°±3.9° and directivity of 6.94±0.38 dBi with the reflection coefficient ≤ -10.5 dB and the isolation between the ports ≥ 20.5dB. High cross polarization discrimination ratios were also achieved within the desired frequency bands.