Design of wide dual-passband microstrip bandpass filters with comb-loaded resonators

Novel microstrip bandpass filters with comb-loaded resonators are proposed. With comb-loaded resonators, the proposed bandpass filter can have a wide passband. In particular, dual passbands show up around 2.45 GHz and 5.75 GHz and their bandwidth is 780 MHz. In addition, by properly controlling passband's coupling coefficient, two passbands' bandwidths of the dual-passband bandpass filter will be controlled properly. Finally, the agreement between measured results and the theoretical prediction validates the proposed structure.