An optimized filter design based on stepped impendence resonators

This paper puts forward an optimized stepped impedance resonator (SIR)-based filter design which is able to optimize the frequency selectivity of the filters by means of an improved filter feeding method. This paper provides a filter design based on SIR. With this design, the zero-degree feeding structure can be achieved through the adjustment of the positions to tap feed lines. The frequency selectivity of the filters is thus improved. Thanks to the small size and simple construction, this type of filter can be widely applied in wireless communication fields.