A wideband planar monopole antenna with an L-shape ground plane is presented. The antenna also has a frequency-notching characteristic. By etching a half-wavelength U-shaped slot in the interior of the radiation element, the frequency-notching characteristic has been created. This paper presents the design and experimental results of the proposed antenna. Moreover, the study also investigates the tuning effects of the geometry parameters on the impedance matching. (c) 2005 Wiley Periodicals, Inc.