基于超材料的双频双圆极化北斗导航天线设计

Design of dual-band dual-circularly polarized BeiDou navigation antenna based on metamaterial

基于超材料结构提出并设计了一种应用于北斗卫星导航系统的双频双圆极化短报文通信天线。天线结构为由16个I形超材料单元和17个Γ形超材料单元构成的单臂平面螺旋,采用单点馈电方式进行馈电。利用超材料可以在不同频段分别产生负相移常数和正相移常数的特性,实现在北斗L频段辐射左旋圆极化波、在S频段接收右旋圆极化波的特性。结果表明,天线在1.615 GHz频率处辐射左旋圆极化波,增益约为3.6 dBi,在L频段,S_(11)<-10 dB的带宽约为8%,3 dB轴比带宽约为6%;天线在2.492 GHz频率处接收右旋圆极化波,增益约为4.85 dBi,在S频段,S_(11)<-10 dB的带宽约为12%,3 dB轴比带宽约为5.5%,满足北斗卫星导航系统短报文通信的要求。

A metamaterial-based antenna was proposed and designed to achieve dual-band dual-circularly polarized BeiDou navigation short message communication.The antenna was a single-arm planar spiral which is consisted of 16 I-shaped and 17Γ-shaped metamaterial unit cells,and fed by single point.The metamaterial was used to radiate(receive)left(right)-handed circularly polarized waves in BeiDou L-band(S-band)due to the negative and positive phase constants produce in different frequency bands by the metamaterials respectively.The results show that at 1.615 GHz the antenna radiates lefthanded circularly polarized wave with gain of 3.6 dBi.In the L-band,the bandwidth of S_(11)<-10 dB is approximately 8%,and the bandwidth of axial ratio<3 dB is about 6%.At 2.492 GHz,the antenna receives right-handed circularly polarized wave with gain of~4.85 dBi.In the S-band,the bandwidth of S_(11)<-10 dB is about 12%,and the bandwidth of axial ratio<3 dB is about 5.5%.These design parameters meet the requirements of BeiDou satellite navigation system for short message communication.