Design of a directional ultra-wideband planar antenna array

The design of a directional ultra-wideband printed circular monopole antenna array operating in 3.1-10.6 GHz is proposed in this paper. The two elements of the array are fed by a broadband T-junction power divider. The antenna's occupied bandwidth of the return loss on a -10 dB level is 7.98 GHz which is from 2.74 GHz to 11.65 GHz where the octave band is 4.25. The gains are 5.25 dB at 3 GHz, 7.56 dB at 6 GHz and 8.62 dB at 9 GHz, respectively. The final size of this antenna is 28.4×67 mm
²
, and the thickness is 1 mm. The proposed antenna array could be easily integrated and apply to the directional long-distance terrestrial UWB communication systems effectively.