A compact ultra-wideband (UWB) planar antenna with reconfigurable band-notched characteristics is proposed in this paper. The proposed antenna covers the frequency band from 3GHz to 11GHz (S11 ≤ -10), with 114% fractional bandwidth. A T-shaped on the ground is used to widen the band of the antenna. Dual arc-shaped slots are embedded on the patch, to obtain the (WIMAX) 3.3-3.6 GHz and (WLAN) 5.1-5.9 GHz notched bands. The reconfigurable band-notched characteristics are achieved by adding PIN diode in the arc-shaped slot. When the PIN is conductive by adding DC voltage source, the notched band is disappeared with good UWB characteristic. The measured results have a good agreement with the simulated results. Because of its compact area and low cost, the proposed antenna is suitable for the UWB communication.