Compact Wideband Bandpass Filter Using Stepped Impedance Resonators Loaded by Open Stubs

Abstract

A compact bandpass filter has been investigated in this paper, the filter has four stepped impedance resonators, six open stubs are loaded on the two inner resonators, by adjusting sizes of six open stubs, a wide passband can be obtained. This proposed filter contributes respectively one transmission zero on either side of the wide passband. The proposed topology is demonstrated with a design operating at 5.205 GHz with 20.2% bandwidth, and more than 20dB of spurious suppression from 0 to 4.26 GHz and from 6.27 to 8.85 GHz is demonstrated in experimental results, which match well with the simulated results.