Abstract: A swallow-tailed planar ultra-wideband antenna with dual band-notched characteristics is proposed. The tapered symmetrical structures of the elliptical radiating element and trapeziform ground ensure a good impedance match over a broad frequency range. The dual band-notched characteristics are achieved by inserting two different-shaped slots in the radiating element. The simulated and measured results show that the bandwidth defined by VSWR 〈 2 of the proposed antenna is from 2 to 14GHz, except the bandwidths of 3.2 - 4.3GHz and 5.3 - 6.2GHz. Moreover, the novel monopole antenna exhibits a good radiation pattern. A conceptual circuit is given for explanation of the band-notched characteristics at the end of the manuscript.