Pedestal substrate integrated waveguide filter with both electric and magnetic cross-couplings

摘要

In this paper, the recently proposed Pedestal Substrate Integrated Waveguide (SIW) structure, consisting of evanescent-mode SIW cavities, loaded with pedestal-shaped metal inserts, is utilized to design a coupled resonator filter with both positive and negative cross-coupling. It is shown that both types of coupling, for a large range of coupling values for both, can very simply be implemented in this structure, with electric coupling obtained by means of an I-shaped strip_line between pedestal tops, and magnetic coupling obtained using inductive irises. The proposed structure can also introduce mixed coupling. Graphs are presented to show the range of coupling values attainable. A proofof-concept sixth order cross-coupled bandpass filter, with a 5 % bandwidth at 5 GHz, and both real and imaginary axis transmission zeros, are designed and measured.