A broadband circularly-polarised monopole antenna is proposed. The broadband property of the antenna is basically achieved not only by the chifre-shaped monopole radiator, but also its asymmetric feed. The circular-polarisation characteristics are greatly enhanced by adjusting the location of the monopole microstrip-feed. The antenna delivers good performance on impedance matching and circular polarisation. The measured results demonstrate that the impedance bandwidth is 72% and the 3-dB axial-ratio bandwidth reaches 41.6% with a central frequency of 2.5 GHz.