Broadband stacked annular ring

Two broadband stacked configurations, composed of a printed annular ring as driver and a parasitic circular disk with and without superstrate have been presented. A maximum bandwidth of 380 MHz has been obtained for both of them by experimental optimization of the design parameters involved (spacer height, parasitic size and feed location). Radiation patterns have been shown at the central and edge frequencies, with average crosspolar components better than 17dB. The antennas are studied within the context of cellular radio systems