一种新型宽频带全向天线的设计

Design of a novel broadband omnidirectional antenna

全向天线在下一代宽带移动通信中有着广泛的应用，本文设计了一种新型的交叉馈电宽频带全向天线，通过加宽振子和加载巴伦实现了天线的宽带特性，使用平行耦合双线对两个宽带对称振子进行交叉馈电。本文通过对半波振子天线的理论分析，HFSS仿真软件的计算和加工并实测得到：天线印制在厚度为 1.5mm，介电常数 εr=2.55 的介质板上，实测电压驻波比带宽 44.7%（VSWR〈2.0）,并且在整个频段内方向图不分裂，在设计的频段内方向图不圆度小于2.3dB，增益大于1.6dB。该天线结构简单，易于加工，实用性很强。

The omnidirectional antennas have been widely used in the next generation of wireless communication systems.A novel cross feed broadband omnidirectional antenna is presented in this paper.The wideband is realized by adding the bulun and wider dipole.Two elements are cross-fed by parallel broadside coupled lines to actualized impedance match.Theoretical analysis of dipole and simulation results with HFSS and measurements of the antenna show that the antenna fabricated on the substrate with thickness of 1.5 mm and relative permittivity of 2.6 can achieve an impedance bandwidth of 44.7% for VSWR＆lt;2.The far-field radiant characteristics are good.The out-of-roundness is less than 2.3 dB and the gain is higher than 1.6 dB.The antenna is simple in structure and easy to fabricate,and it has a wide application.