Novel Compact Interdigital Bandpass Filters with Multilayer Stepped Impedance Resonators/Folded Quarter–Wavelength Resonators

Abstract

Novel compact interdigital bandpass filters (BPFs) which used multilayer stepped impedance resonators (SIRs)/folded quarter–wavelength resonators were presented. Two measures were taken to reduce the sizes of the proposed filters. Firstly, two resonators (SIRs and folded quarter–wavelength resonators) with novel structures were designed. Secondly, all the designed resonators were located on different dielectric layers. The proposed interdigital BPFs, which were simulated with the high frequency structure simulator (HFSS), show excellent performance and could realize the miniaturization purpose. Furthermore, it is found that the proposed filter with folded quarter–wavelength resonators is more excellent in realizing miniaturization and improving performance than that with SIRs.