A compact circularly polarized antenna for the Global Navigation Satellite System L1 band at 1575 MHz is presented. A circular patch antenna is first designed to operate before being integrated with four ring slots to achieve the circular polarization. The antenna features a bandwidth of 1.15 % in L1, with an axial ratio bandwidth of 0.58 %. The antenna radiates towards 0° with a realized gain of 4.4 dB and an angular beamwidth of 101.3°.
