We present an ultra-wideband bandpass filter with -15dB suppression between 5.15-5.8GHz utilizing second order band elimination filter (BEF). The filter consists of a modified step impedance resonator (SIR) and two interdigital coupled line. Two parallel coupled stubs are attached to the SIR to create a second order BEF, which introduce a sharp and wide enough notch. HFSS was used to optimal the structure, and the measured result shown a good agreement with the simulated one. The 3dB bandwidth of the UWB Bandpass filter are between 3.1-4.8GHz and 6.1-10.2GHz.