Design of Wideband GNSS Antenna With Wide-Angle Circular Polarization and Anti-Multipath Performance for High Precision Marine Positioning

Abstract

In the paper, a wideband GNSS antenna with wide-angle circular polarization and anti-multipath performance is proposed. By using the coupled feeding formed by arc-T-shaped patch, wide bandwidth is obtained. Eight short-circuit pins are loaded around the radiation patch for widening the 3-dB axial ratio (AR) beamwidth at the GNSS frequencies and reducing size. Furthermore, two groups of bent metal-branches are loaded on the slotted ground for front-back ratio (FBR) enhancement at the GNSS frequencies. To provide uniform circular polarized (CP) excitation with small occupied area, a compact wideband quadrature feed network with amplitude imbalances within 1 dB and phase imbalances within 5° is designed which covers the GNSS band. For validation, a prototype is fabricated. Measurement results show that an overlapped bandwidth of more than 45% is obtained for 10-dB return loss and 3-dB AR. At the frequencies of 1.207 GHz, 1.227 GHz, 1.247 GHz, 1.561 GHz, 1.575 GHz and 1.602 GHz, the measured 3-dB AR beamwidths and FBRs are all larger than 200° and 20 dB, respectively, which demonstrates the potential of high precision positioning at GPS L1/L2, BDS B1/B2, GLONASS L1/L2, and Galileo L1/E5b bands.