Multilayer folded-waveguide dual-band filter

This paper presents a primary investigation into developing a compact dual passband filter using novel folded-waveguide resonators with a multilayer structure. A new coupling scheme for dual-band operation is realized. Both slot and aperture couplings are used for the implementation. For the demonstration, a 4-pole dual-band filter of this type has been designed, fabricated and tested. Simulation and experimental results are presented to validate the design and to show the advantages of this type of filter.