Design of A Vertically Stacked Substrate Integrated Folded-Waveguide Resonator Filter in LTCC

This paper proposes a vertically stacked substrate integrated folded-waveguide (SIFW) filter in a multilayer low- temperature cofired ceramic (LTCC) structure. The folded waveguide resonators are used to miniaturize the circuit size. The vertical metal walls of the resonators are realized by closely spaced metal filled vias. A four-pole Chebyshev waveguide filter has been designed and fabricated. From the result, the footprint of the filter can be reduced to 26.3% as compare to a conventional planar direct-coupled waveguide filter.