A novel bandstop filter (BSF) with a stop band covering GSM-900, GSM1800. Bluetooth, and future 5 GHz applications which possesses the characteristics of compact size and snide bandwidth is proposed and,fabricated. Parameters are optimized via numerical simulations. Die simulations are performed via an in-house-prepared three dimensional (3D) finite-difference time-domain (FDTD) package. Measurements ore carried out using an HP-8510C network analyzer. The simulated and measured results show that the filter has wide stopband of 126% (1.7-7.8 GHz) for 3-dB bandwidth. There is a good agreement between the simulated and experimental results. (C) 2008 Wiley Periodicals Inc.