Abstract: Ultra-Wide Band (UWB) is promising technology for many wireless applications due to its large bandwidth, good ratio of transmission data and low power cost. The main goal of this work is to design an UWB filter suitable for that purpose in the frequency band 3.1-10.6 GHz. In order to achieve that goal, one UWB filter configuration is investigated, designed and characterized. Theoretical analysis is done to compute the filter parameters, such as the return loss, insertion loss and attenuation characteristic over the full frequency band. The size of this filter is also studied because of its important aspect on the frequency behavior.