Effective Extracting Method for Electromagnetic Parameters of Periodically Loaded Substrate Integrated Waveguide Units

An effective approach for electromagnetic characterization of periodically loaded substrate integrated waveguide (SIW) units is presented. Anisotropic material dispersion analysis is carried out to provide a theoretical basis for extracting the effective permeability tensor of the unit structure. A detailed procedure is described in this paper, and applied to an improved polyline-patterned unit cell. The new structure improves the relative effective permeability by 0.25 compared to the original topology over the entire frequency band of interest. Further, a double-layer loading topology is studied and a relative effective permeability of 3.25 is obtained. A set of comparison tests based on SIW resonators loaded with proposed unit cells exhibits an up to 66% sizereduction. Less than 1.4% of the relative error is achieved, illustrating its suitability to explore the miniaturization potentials of any type of unit cell and with it to make an accurate evaluation of periodic loading SIW performance.