Abstract: The design of a directional ultra-wideband printed circular monopole antenna array to operate in the 3.1-10.6 GHzUWB is proposed in this paper. The two printed circular monopole antennas are fed by broadband T-junction power divider. Theantenna has an occupied bandwidth of the return loss on a -10 dB level is 7.98 GHz which is from 2.98 to 10.96 GHz, and the octaveband is 3.68. The gains are 3.54 dB at 3 GHz, 5.03 dB at 6 GHz and 5.67 dB at 9 GHz, respectively. The final size of this antennais 28.4×67 mm2, and the thickness is 1 mm. The characteristic of direction is obtained effectively, and hence the antenna can beused in the directional long-distance terrestrial broadband communications