This paper describes the design of a broadband Global Navigation Satellite System (GNSS) antenna structure with excellent axial ratio characteristics of circular polarization at low observation angles to suppress multipath signals caused by surrounding interferences. The proposed antenna has a structure in which a quadrature printed broadband dipole antenna element and a broadband dual-feed circuit with 90o phase delay are integrated to form a circularly polarized signal at a wide bandwidth (1.145 ~ 1.615 GHz). In order to provide excellent axial ratio performance of less than 3.5 dB at a wide viewing angle of -78o to +78o, a pair of tooth-shaped conductor patterns with regular spacing on the outer surface of the cylindrical radome (except the forward radiating region) is realized. The size of the integrated broadband GNSS antenna is less than 135 (D) x 90 (H) mm.

Keywords: broadband GNSS Antenna, circular polarization, axial ratio, multipath