In‐line ports feeding substrate integrated waveguide resonator with higher order modes suppression

Abstract

In-line ports are usually used to feed substrate integrated waveguide (SIW) resonator in an in-line transmission circuit. However, the higher order mode TE 102 is excited as well as the fundamental mode TE 101 thereby deteriorating the selectivity. Here the authors present a method to remove the selectivity deterioration. By additionally introducing TE 201 , the TE 102 and the TE 201 can be counteracted with each other by taking advantage of their out-phase out-coupling, and then both modes are suppressed well in a SIW resonator feeding with in-line ports. Two prototypes based on square and rectangle cavity are fabricated, respectively and measured to verify the proposed technique. The results agree with the expectation well. It shows the potential to be implemented in the in-line transmission circuit with SIW resonator.