Department: Departamentos de la UMH::Ingeniería de Comunicaciones
Issue Date: 2019-10-15
In this work, the study of two different topologies of S-band band-pass filters based on periodic
structures in substrate integrated waveguide (SIW) technology is theoretical and experimentally
addressed. The first topology consists of periodic rectangular perforations of the SIW substrate.
In this filter topology, the lower cutoff frequency is determined by the cutoff frequency of the
first Floquet mode of the periodic structure, while the upper cutoff frequency and the rejection
band are conditioned by its first band-gap. The second topology consists of a periodic array of
square complementary split-ring resonators (CSRRs) etched on the waveguide surface. In this case,
the use of subwavelength resonators with evanescent-wave transmission leads to a much smaller
filter, given that the pass-band is below the cutoff frequency of the waveguide. The effect of the
different dimensions of the unit cell in the filters characteristics (lower cutoff frequency, pass-band,
and rejection-band associated to the first band-gap of the periodic structure) is analyzed through
the dispersion diagram of the periodic cell. Finally, two band-pass filters based on each topology
have been designed and built, showing in both cases good matching and low insertion loss in the
pass-band, and a deep rejection band.