Analysis and Design of an UWB Band pass Filter with Improved Upper Stop band Performances

In this work, we are interesting in the analysis and the design of an ultra wideband (UWB) band pass filter with improved upper stop band performances, using microstrip lines. The design of the UWB band pass filter is based on the use of stepped-impedance low pass filter and high pass filter; whereas the simulation of its frequency response ([S]) is done using MATPAR software and it is based on the electromagnetic (EM) parameters for each section of line forming the band pass structure. Our filter with bandwidth between 2.9-10.8 GHz, measures just 12.6 1.524 31.58 mm and was fabricated using RT/D 5880 substrate by means of stepped-impedance 5-pole microstrip low pass filter and high pass filter constructed from quasilumped elements. The simulated results of stop band performances are better than 15 dB for a frequency range up to 25 GHz.