【作者】 冯攀； 许光辉； 陈星；

【Author】 Feng Pan;Xu Guanghui;Chen Xing;School of Electronics and Information Engineering,Sichuan University;

【机构】 四川大学电子信息学院；

【摘要】 定向天线设计中,常利用金属反射面提高天线定向增益。为了实现天线正向波和经反射面的反射波同相位,通常天线辐射单元和反射面之间距离为1/4波长,这严重限制定向天线的宽带特性。本文提出了采用多层FSS(FrequencySelectiveSurface,频率选择表面)与平面金属地一起构成定向天线的多层地结构,利用FSS对不同频率电磁波的透射和反射特性,使不同频率段电磁波对应有不同的辐射单元到反射面的距离,有效地克服金属地对定向天线宽带特性的制约。本文采用上述多层地结构和平面微带圆锥偶极子辐射单元设计了一款超宽带定向天线,测试结果表明:天线|S11|≤-10dB阻抗带宽达到140%(2.3GHz～13GHz);在2.3GHz～9.4GHz频率范围内,天线有良好的定向特性,天线增益大于6dBi,最大增益为13.1dBi。更多还原

【Abstract】 In the design of directional antennas,metal reflectors are commonly employed for enhancing antennas’ directional gain.But to realize the in-phase between the forward wave and the reflecting wave through a metal reflector,the distance between an antenna’s radiation elements and metal reflector should be 1/4 wavelength,which seriously limits the bandwidth of a directional antenna.In this paper,a novel ground structure,namely a multi-layer ground,is proposed to achieve the UWB(ultra-wideband) feature for a directional antenna.It consists of multiple FSS(Frequency Selective Surface) layers and a metal ground.By making use of the penetrating and reflecting characteristics for the electromagnetic wave at different frequencies,this structure allows the distance between the radiation element and the metal reflector varies with the working frequency,and so thus it is able to overcome the limitation effect of the metal ground on directional antennas’ UWB features.An UWB directional antenna using the aforementioned multi-layer ground and the planar microstrip conic dipole is designed.Measured results show:the antenna’s |S11 |≤-10 dB impedance bandwidth is up to 140%(from 2.3 GHz to 13 GHz);over a frequency band from 2.3 GHz to 9.4 GHz,it has good directional performances with gain larger than 6 dBi and a maximum gain of 13.1 dBi.更多还原