Parametric study of dispersion and filtering capabilities of SRR-type FSS loaded rectangular waveguides

An array of metallic patches printed over the surface of a grounded dielectric slab is known as a frequency selective surface (FSS). When such an FSS loaded slab is placed within a waveguide, special features such as bandgaps and TEM behavior can be achieved. Just like other metallic inclusions, split ring resonators (SRR) can also be used to realize such FSS-loaded waveguides. Due to its inherent ability to create backward waves, SRR-type FSS loaded waveguides can support backward traveling modes. This characteristic has been experimentally shown. Since these modes exist only within a finite band, such waveguides can potentially exhibit bandpass filtering capabilities. This is achieved when the backward passband is below the cutoff frequency of the dominant ordinary waveguide mode.