Modeling substrate integrated waveguide structures using effective material properties

A substrate integrated waveguide is analyzed using effective material properties for the first time. The analysis is performed by replacing subwavelength periodic metallization with a frequency dependent homogeneous material. For example, the post wall of the waveguide is represented as a negative permittivity material. A substrate integrated waveguide fabricated in low temperature co-fired ceramic is analyzed. The phase constant of the guide is calculated with slab waveguide equations, using effective material properties to replace much of the metal structuring, and it is shown to be almost the same as that simulated and measured. An SIW coupler that utilizes side wall leakage for coupling is simulated using effective material properties. The simplified structure shows results matching the full structure with a reduction in simulation time of 88%. These results demonstrate a substrate integrated waveguide can be accurately and efficiently simulated by replacing subwavelength periodic structures with a frequency dependent homogeneous material.