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.