Cantor Dielectric Filters in Rectangular Waveguides

Abstract

A triadic Cantor fractal multi-layer is a stack of two different dielectric materials whose thicknesses are determined according to the triadic Cantor fractal scheme. When inserted in a rectangular waveguide, the spectral response of a triadic Cantor multi-layer can be tailored to feature a narrow single transmission peak in the waveguide single-mode frequency range, with a low insertion loss and a high rejection level of forbidden frequencies. The experimental characterization of alumina-polystyrene and plexiglass-polystyrene Cantor multi-layers inserted in a WR90 waveguide (Hewlett-Packard, USA) matches thoroughly with the results of the theoretical modeling and demonstrates that triadic Cantor multi-layers can be used to realize feasible narrow-band microwave filters.

Keywords:

• fractal dielectric multi-layers
• electromagnetic band gaps
• waveguide devices

Acknowledgments

This work has been sponsored in part by the Italian Ministry of University and Research (PRIN 2006, Study and Realization of Metamaterials for Electronics and TLC applications).

Shikik T. Johnson would like to express sincere gratitude to the National Science Foundation Postdoctoral International Research Fellowship Program (IRFP; Award number 0602033 [2006–2008]), for full financial support enabling him to undergo this research endeavor.