Evanescent-Mode Bandpass Filters Using Folded and Ridge Substrate Integrated Waveguides (SIWs)

A novel evanescent-mode bandpass filter (BPF) is presented using folded and ridge substrate integrated waveguides (FSIWs & RSIWs). Both measured and simulated S-parameters are presented to show the characteristics, with good agreements achieved between them. It is experimentally validated that such a BPF has better performance in spurious suppression and much smaller size than those of conventional SIW cavity-coupled counterparts.