ABSTRACTA novel dual band-notched ultra-wideband (UWB) planar antenna with improved characteristic in 5.5 GHz WLAN notched band is presented. Two kinds of L-shaped slots are inserted in the radiator in order to obtain the dual notched characteristics. A separated strip is added in the middle of the U-shaped radiator for further improving the performance. The antenna has a measured impedance bandwidth of 3.1–11.0 GHz with VSWR < 2, while it has dual notched bands of 3.4–4.0 GHz and 4.9–6.0 GHz. Besides, the equivalent circuit model, transmission line model and transfer function are also studied to investigate the band-notched performance of the proposed antenna.