An antenna for circularly polarized radiation at an operating frequency in excess of 200 MHz has a substrate in the form of a disc-shaped dielectric tile with parallel planar surfaces. The upper surface bears a conductive pattern including a resonant ring and a number of open-circuit radiating elements each having an electrical length of a quarterwave at the resonant frequency of the ring. The radiating elements extend outwardly from the ring and are joined to the ring at uniformly spaced locations. Each radiating element extends in a direction which has both a radial component and a tangential component and follows a generally spiral path. A pair of central feed nodes are coupled to the inside of the ring by a pair of feed tracks lying on a diameter. Dual-frequency and dual-polarization variants are also disclosed.