Design of circularly polarized annular slot antennas for satellite navigation systems

This paper presents the study of two different circularly polarized annular slot antennas designed for the global positioning system (GPS). The antennas are designed for the operation in the L1-band. The design procedure is briefly described. Numerical results show that both antennas present good performance in terms of impedance matching and circular polarization purity. In comparison to other geometries found in the literature, one of the topologies discussed in this contribution exhibits high robustness against fabrication tolerances. It should be pointed out that both proposed antennas can be constructed by using only one layer of microwave laminate, hence yielding low-cost solutions for high precision GPS-based navigation systems.