In this paper, a simple method to obtain a notch in the ultra-wideband (UWB) bandpass filter is presented. UWB bandpass filter is designed using ground plane aperture technique. To reject the undesired wireless local area network (WLAN) signals, a complementary single split ring resonator (CSSRR) is placed under the coupled lines of the bandpass filter. The CSSRR has flat insertion loss and good roll off rate than the conventional complementary split ring resonator (CSRR). The proposed filter offers an ultra wide bandwidth bandpass filter characteristics with a steep notch function around 5.5GHz. Hence the interference from the devices operated in the IEEE 802.11a spectrum can be avoided properly. IE3D simulation results of the notched UWB bandpass filter is in good agreement with the measurement results.