Bandwidth Enhancement Of Broadband Dual-Polarized Antennas For Base Station Applications

Antennas for base stations are the key component in mobile communication systems,which directly affect the overall performance of the entire wireless networks.With the development of communication technology,different mobile communication systems have designated with different frequency bands,which need dual-polarized,broadband,miniaturized base station antennas.Therefore,it is valuable to investigate the bandwidth enhancement of broadband dual-polarized antennas as well as the miniaturization technology.The main contributions of this work are summarized as follows:1.A bandwith-enhanced broadband dual-polarized antenna is proposed.The proposed antenna consists of a broadband four-leaf dual-polarized element,which is composed two perpendicularly crossed diamond-shaped dipoles,which form a shaped of four diamond arms and fed by a coaxial line a circular-shaped slot etched on each arm of the dual-polarized element which achieve a broadband bandwidth of 45%（1.7-2.7 GHz）.A parasitic circular disk with four pasasitic strips is above the dual-polarized enement and a parasitic loop is below the dual-polarized element for further bandwidth enhancement.The simulated and measured results show that the bandwidth for |S11|<-15 d B covers the band 1.4-2.75 GHz（63.4%）with an isolation of about 30 d B.The antenna gain is about 9 d Bi and the half-power beamwidth（HPBW）is roughly 70°±8°.The total size of the antenna is 0.93λ₀ × 0.93λ₀ × 0.3λ₀（λ₀ is the free-space wavelength at the center frequency 2.1 GHz）.2.The bandwidth of a dual-dipole dual-polarized antenna is enhanced.The proposed antenna consists of two perpendicularly crossed dual-pipoles enements,each of which is made of two parallel dipoles and fed by a coaxial line.A parasitic circular disk is placed above the dual-polarized dual-dipoles antenna fot bandwidth enhancement,featuring a reduced antenna size.The simulated and measured results show that the bandwidth for |S11|<-15 d B covers the band 1.4-2.7 GHz（63%）with an isolation of about 30 d B.The antenna gain is about d Bi and the half-power beamwidth（HPBW）is roughly 60°±8°.The total size of the antenna is 0.68λ₀ × 0.68λ₀ × 0.38λ₀.3.The size of the bandwidth enhanced four-leaf dual-polarized antenna is miniaturied.The proposed antenna consists of a broadband dual-polarized element,which is composed two perpendicularly crossed diamond-shaped dipoles,forming a shaped of diamond arm and fed by a coaxial line.A broadband bandwidth of 45%（1.7-2.7 GHz）has been achieved for the dual-polarizd element.A U-shaped slop etched on each leaf of the dual-polarized element and a parasitic element that is comprised of two layers of circular metal disks are introduced for further bandwidth enhancement.The simulated and measured results show that the bandwidth for |S11|<-15 d B covers the band 1.39-2.8 GHz（67%）with an isolation of about 30 d B.The antenna gain is about 9 d Bi and the half-power beamwidth（HPBW）is roughly 65°±5°.The total size of the antenna is 0.464λ₀ × 0.464λ₀ × 0.35λ₀.An eight-element bandwidth enhancement of a broadband dual-polarized antenna array is developed for base station application.The bandwidth enhanced broadband dual-poliarzed antennas proposed in this paper may find wide aaplication in base stations for 2G/3G/4G and IMT systems.