Dielectric loaded cavity filter with wide spurious free region and better out-of-band rejection

Abstract

Spurious modes suppressions are compared between the dielectric-loaded cavity filters with cylindrical and rectangular structures in this paper. Using mode matching method Mode charts are computed to analyze that. The comparisons show that the cylindrical cavity filter has better spurious response. Also filter with cross-coupling is discussed, which has sharper out-of-band rejection. Three experimental filters are designed. And the measured results have good agreement with the analysis.