摘要

The folded substrate-integrated waveguide (FSIW) takes the advantages of more compact size and higher integration than the conventional SIW structures, probably resulting in a very compact design. One simple narrow-slot bandpass filter is thus proposed and implemented to demonstrate the superiority of FSIW structure. The design strategies of the bandpass filter are introduced. One prototype with three narrow slots in the middle layer of FSIW is fabricated to demonstrate the validity of the proposed design. For the sake of measurement, one back-to-back stripline transition is also designed. The measured results are in good agreement with the HFSS-simulated results, which indicates that the bandwidth is about 15%; the insertion loss is less than 1.5 dB. In addition, the rejection band of this filter is quite wide, implying very good harmonic rejection.