基于非对称U型槽的GPS微带天线设计

GPS microstrip antenna based on asymmetrical U-shape slit structure

针对GPS接收机天线的发展需要,结合目前宽频化与圆极化微带天线的设计技术,提出了一种基于非对称U型槽的GPS微带天线。利用在辐射贴片上加载非对称U型槽缝,实现了圆极化与宽频化设计。重点分析当天线左右槽缝长度做非对称变化时,对天线轴比(axial ratio,AR)和圆极化等性能参数的影响。天线仿真及测试结果表明,3 dB圆极化带宽为21 MHz(1.562～1.583 GHz),在中心频率处的右旋圆极化轴比为1.19 dB,天线E面(φ=0°)与H面(φ=90°)的3 dB空域覆盖分别达143°(-76°～67°)和176°(-90°～86°),且右旋圆极化(right-handedcircular polarization,RHCP)电平均大于其交叉极化左旋圆极化(left-handed circular polarization,LHCP)电平,具有较好的阻抗带宽和广角圆极化空域分布特性、较强的抑制交叉极化和抗多径干扰的能力,能满足GPS接收机的实际应用需求。

In view of the trend for GPS receiver antenna,combining with the antenna broadband and circular polarization technology,based on the research of microstrip antenna,an asymmetrical U-shaped groove-based GPS microstrip antenna is proposed in this paper.We are introducing an asymmetrical U-shaped slit which is loaded on the radiation patch to obtain broadband and circular polarization characteristics.It can focus on the impact of the performance parameters for axial ratio（AR） and right circular polarization when the asymmetric slightly changes in the left and right slot.The simulation results show that the bandwidth of 3dB circular polarization is 21 MHz（1.562~1.583 GHz）,the right-handed circular polarization axial ratio at center frequency is 1.19 dB,the 3 dB airspace covered for E-plane（φ=0°） and H-plane（φ=90°） of the antenna is 143°（-76°~67°） and 176°（-90°~86°）,respectively.And the right-handed circular polarization（RHCP） levels are all greater than its cross-polarization of left-handed circular polarization（LHCP） level.The proposed antenna has a good impedance bandwidth and the airspace distribution of wide-angle circular polarization,as well as a strong ability to suppress the cross polarization and anti-multipath interference.The simulation and measuring results show that the proposed antenna meets the demands for practical application of the GPS receiver.