Sieganschin, AntonAntonSieganschinTegowski, BartoszBartoszTegowskiJacob, ArneArneJacob2022-07-062022-07-06202251st European Microwave Conference, EuMC 2021 (2022)http://hdl.handle.net/11420/13043This contribution presents a compact filter with a novel folded circular substrate integrated waveguide (FCSIW) cavity. A modification leads to dual-mode operation. Two of these cavities are combined to form a fourth order filter. The design idea is experimentally verified with a very compact 10 GHz filter featuring an insertion loss below 2.4 dB in a 1 GHz bandwidth. The out-of-band rejection exceeds 40 dB between 11.1 GHz and 30 GHz.enCompactfilterfolded substrate integrated waveguide (FSIW)substrate integrated waveguide (SIW)X-bandConference Paper10.23919/EuMC50147.2022.9784369Conference Paper