Abstract: In this paper, a new broadband circularly polarized dielectric resonator antenna is designed, It is consist of a rat race shaped broadband 90 °phase shift 1 :4 splitter microstrip feed network, and a dielectric resonator. The antenna structure is compact,the process is simple, simulation and experimental results are in good agreement, the overlapping part for the impedance bandwidth and less than 3dB axial ratio bandwidth is from 1.09 GHz -1.83GHz(50.7%). The beamwidth for gain greater than 3dB and the axial ratio less than 3dB is reached 90 °. Antenna operating frequency band covers the four navigation system, including China's Compass system, the U. S. GPS system ,the European GALTLEO system and Russia's GLONASS system. The antenna can be applied to the global satellite navigation , positioning system and wireless broadband communication system.