Design of a Circularly Polarized Wideband Antenna for Global Positioning Systems

This paper proposes a three-dimensional circularly polarized antenna design for Global Positioning Systems (GPS) use. The overall dimensions of the antenna are $0.3 \lambda \times 0.3 \lambda \times 0.09 \lambda$, where $\lambda$ is the free space wavelength at 1370 MHz, designed on an FR4 substrate. The antenna exhibits wideband characteristics regarding both reflection loss and axial ratio bandwidth. The $\mathrm{L} 1, \mathrm{~L} 2$, and $\mathrm{L5}$ bands, the simulated and measured voltage standing wave ratio (VSWR), and the axial ratio are below 2 and 3 dB, respectively.