DESIGN OF NOVEL BANDPASS FILTER USING OPTIMUM SHORT CIRCUITED STUB TECHNIQUE FOR WIRELESS COMMUNICATION

Abstract

In this paper optimum distributed microstrip structure ultra wideband (UWB) band pass filter (BPF) with sharp roll-off characteristics is presented for wireless communication. Here design of new UWB BPF with Multiple-mode resonator (MMR) and the stub loaded stepped impedance stub loaded resonator (SISLR) is given with detailed analysis using MoM based IE3D simulation software.  Its resonance behavior is thoroughly characterized so as to allocate the five resonant frequencies in the UWB pass band within 3.1-10.6 GHz band. The novel stub loaded stepped impedance stub loaded resonator is found to have the advantage of providing more degrees of freedom to adjust the resonant frequencies in the UWB pass band. For the novel UWB filter and the differential mode of the designed balanced filter, three transmission zeros at the pass band are realized by using SISLR, which enhances the pass band selectivity of these filter. The simulated results are in good agreement, showing good UWB filtering performance with sharp rejection skirts outside the pass band. The analytical and accurate design equations for transmission poles and zeros of these are provided based on the scattering-parameters theory for SISLR.