Design of highly selective ultra-wideband bandpass filter using multiple resonance resonator

In this paper a highly selective ultra-wide band (UWB) bandpass filter is designed using interdigital parallel coupled lines (IDPCL) and multiple resonance resonator (MRR). Interdigital capacitor (IDC) is used to achieve strong coupling between short circuit stubs. Mixed coupling produced by IDC and coupled short circuit stubs introduce a finite transmission zero. This transmission zero will increase the selectivity on lower side of passband. MRR produces four transmission poles whereas total of six transmission poles are archived in the passband by using IDPCL at input/output. Proposed design is fabricated. Simulated and measured results are well correlated.